remove_dashboard_menu_item.php

<?php
/*
 * This will remove the "Dashboard" menu item
 * for all users that are not super-admins.
 */

function aristath_custom_admin_theme_remove_menus () {
	if( !current_user_can( 'manage_network' ) ) {
		global $menu;
		$restricted = array( __( 'Dashboard' ) );
		end ( $menu );
		while ( prev( $menu ) ) {
			$value = explode( ' ', $menu[key( $menu )][0] );
			if( in_array( $value[0] != NULL?$value[0]:"" , $restricted) ) {
				unset( $menu[key( $menu )] );
			}
		}
	}
}
add_action('admin_menu', 'aristath_custom_admin_theme_remove_menus', 10);

remove_mysites_menu.php

<?php
/*
 * This will disable the 'my-sites' menu
 * for all users that are not super-admins.
 */

function aristath_remove_mysites_menu() {
  global $wp_admin_bar;
  if( !current_user_can( 'manage_network' ) ) {
    $wp_admin_bar->remove_menu( 'my-sites' );
  }
}
add_action( 'wp_before_admin_bar_render', 'aristath_remove_mysites_menu' );