Overriding paginatorDSRequest to add extra stuff ...

gistfile1.js

//

var dt = new Y.DataTable({
   columns: ...
   
   paginator: .....
   
   requestStringTemplate: "?page={page}&itemsPerPage={itemsPerPage}&sortBy={sortBy}" // or whatever
  
});

dt.plug(  Y.Plugin.DataTableDataSource, {
  datasource: ds
});

dt.render('#tableBar');


// override the paginatorDSRequest method and add your stuff to the request string
dt.paginatorDSRequest = function(requestString) {
  this.datasource.load({
    request: requestString + '&addOne=' + addOne + '&addTwo' + addTwo
  });  
}

// the "processPageRequest" method uses the overridden dt.paginatorDSRequest method above for 
//  each and every page request ...
dt.processPageRequest(1);