A quick example of creating circle objects from data in a Fusion table and adding them to a map...

ft-api-circle-map.html

<style type="text/css" media="screen">
    #map-canvas {width: 620px; height: 600px;}
    .circleBase {
    	-moz-border-radius: 999px; /* Firefox */
    	-webkit-border-radius: 999px; /* Safari and Chrome */
    	border-radius: 999px; /* Opera 10.5+, future browsers, and now also Internet Explorer 6+ using IE-CSS3 */
    	behavior: url(ie-css3.htc); /* This lets IE know to call the script on all elements which get the 'box' class */
    	float: left;
    	}
    .barrettcircle {width: 25px; height: 25px; background: #37949b; opacity: .7}
    .falkcircle {width: 25px; height: 25px; background: #5341BF; opacity: .7}
</style>

<!-- begin scripts -->
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?key=AIzaSyBJj_v-VYk6V7vzOIlIj88DiteiuMfpdN4&sensor=false&region=us"></script>
<script type="text/javascript">
    var fn = fn || {};

    // begin main function
    $(document).ready(function() {
        fn.retrieveData();
    });

    // begin data configuration object
    var fn = {

        // array to hold our circle objects
        countyMap: [],

        // array to hold info windows we construct
        infoWindows: [],

        // retrieve json from fusion table
        retrieveData: function(){
            $.getJSON("https://www.googleapis.com/fusiontables/v1/query?sql=SELECT+*FROM+1OHzhoE2ARzIh0fCfGTn7A9hMIit4neAnlS49oZI&key=AIzaSyBJj_v-VYk6V7vzOIlIj88DiteiuMfpdN4", fn.processData)
        },

        // process json from fusion table
        processData: function(data){

            // see the data coming back from the fusion tables api
            console.log(data);

            // shortcuts for accessing columns
            var cityLatLngColumn = 3;
            var cityNameColumn = 5;
            var precinctsColumn = 4;
            var falkVotesColumn = 6;
            var falkPctColumn = 7;
            var barrettVotesColumn = 8;
            var barrettPctColumn = 9;
            var cityFormulaColumn = 13;
    		var marginColumn = 12;
            var cityColorColumn = 16;

            // loop through the rows to build a circle object for each
            for (var i = 0; i < data.rows.length; i++) {
                var row = data.rows[i];

                // json source has lat/lng in a single column. split it on comma
                var cityLatLngRaw = row[cityLatLngColumn];
                var commaPos = cityLatLngRaw.indexOf(',');
                var lat = parseFloat(cityLatLngRaw.substring(0, commaPos));
                var lng = parseFloat(cityLatLngRaw.substring(commaPos + 2, cityLatLngRaw.length));
                var cityLatLng = new google.maps.LatLng(lat, lng)


                // build our circle object
                fn.countyMap[parseInt(i)] = {
                    'center': cityLatLng,
                    'formula': parseFloat(row[cityFormulaColumn]),
                    'name': row[cityNameColumn],
                    'fillColor': row[cityColorColumn],
    				'precincts': row[precinctsColumn],
                    'falkVotes': row[falkVotesColumn],
                    'falk': row[falkPctColumn],
                    'barrettVotes': row[barrettVotesColumn],
                    'barrett': row[barrettPctColumn],
                    'margin': row[marginColumn]
                }
            }

            // see what our array of circle objects looks like
            console.log(fn.countyMap);

            // create the map based on the div id
            fn.createMap("map-canvas");
        },

        // create the map
        createMap: function(mapDiv){
            var map = new google.maps.Map(document.getElementById(mapDiv), {
                center: new google.maps.LatLng(44.74648547505308, -89.84939737499997),
                    zoom: 7,
                scrollwheel: false,
                draggable: true,
                mapTypeControl: false,
                navigationControl: true,
                streetViewControl: false,
                panControl: true,
                scaleControl: true,
                mapTypeId: google.maps.MapTypeId.ROADMAP,
                navigationControlOptions: {
                    style: google.maps.NavigationControlStyle.SMALL,
                    position: google.maps.ControlPosition.RIGHT_TOP}
            });

            // add our circles to our map
            fn.addCirclesToMap(map);
        },

        // function to add our circles to map
        addCirclesToMap: function(map){

            //begin circle loop
            for (var i = 0; i < fn.countyMap.length; i++) {

                // construct the circle for each value in countyMap array
                var circleOptions = {
                    strokeColor: "#000000",
                    strokeOpacity: 0,
                    strokeWeight: 2,
                    fillColor: fn.countyMap[i].fillColor,
                    fillOpacity: 0.7,
                    map: map,
                    clickable: true,
                    center: fn.countyMap[i].center,
                    radius: fn.countyMap[i].formula * .5
                };

                // create a google map circle
                var countyCircle = new google.maps.Circle(circleOptions);

                // add it to the map
                countyCircle.setMap(map);

                // create an info window based on this circle
                fn.createInfoWindowArray(countyCircle.center, fn.countyMap[i].precincts, fn.countyMap[i].falk, fn.countyMap[i].falkVotes, fn.countyMap[i].barrett, fn.countyMap[i].barrettVotes, fn.countyMap[i].margin, fn.countyMap[i].name, i);

                // add a click event
                fn.attachClick(countyCircle, i, map);

            }

        },

        // function to create an info window and push to an array
        createInfoWindowArray: function(center, precincts, falk, falkVotes, barrett, barrettVotes, margin, name, iwIndex){

            // concatenating a whole lot of html
            recallInfoWindow =
                '<p style=\'font-family: \"Trebuchet MS\", Verdana, sans-serif; font-size: 13px;  color: #555535;\'>' +
                    '<b>' + name + ' County</b><br>' +
                    'Wards reporting: ' + precincts + '<br>' +
                    '<hr style=\"background-color: #e6e6e6; color: #e6e6e6; text-align: center; height: 1px; width: auto;\" />' +
                    '<span style=\'font-family: \"Trebuchet MS\", Verdana, sans-serif; font-size: 13px;  color: #555535; line-height: 15px;\'>' +
                    '<b>Barrett votes: </b>' + barrettVotes + ' - ' + barrett + '%<br />' +
                    '<b>Falk votes: </b>' + falkVotes + ' - ' + falk + '%<br>' +
                    '</span>' +
                    '<hr style="background-color: #ebebeb; color: #ebebeb; text-align: center; height: 1px; width: auto;" />' +
                    '<span class=\'googft-info-window\' style=\'font-family: \"Trebuchet MS\", Verdana, sans-serif; font-size: 18px;  color: #555535; line-height: 15px;\'><b>Margin of win: </b>' + margin + '</span>' +
                '</p>';

            var iwOptions = {
                position: center,
                content: recallInfoWindow,
            };

            fn.infoWindows[iwIndex] = new google.maps.InfoWindow(iwOptions);

        },

        // close an info window if one is open
        closeExistingIWs: function(){
            for (var i = 0; i < fn.infoWindows.length; i++) {
                fn.infoWindows[i].close();
            }
        },

        // open a new info window
        openIW: function(iwIndex, map){
            fn.infoWindows[iwIndex].open(map);
        },

        // add click event to the circle
        attachClick: function(circle, iwIndex, map){
            google.maps.event.addListener (circle, 'click', function(evt) {
                fn.closeExistingIWs();
                fn.openIW(iwIndex, map);
            });
        }
    }
</script>

<!-- begin map container -->
<div id="map-container">
    <div id="map-canvas"></div>
</div>
<!-- end map container -->