Removes the EDD sales summary widget
 * Plugin Name: Easy Digital Downloads - Disable Dashboard Widget
 * Description: Removes the EDD sales sumamry widget
 * Author: Pippin Williamson
 * Author URI:
 * Version: 1.0
remove_action( 'wp_dashboard_setup', 'edd_register_dashboard_widgets', 10 );
To implement this snippet on your site, create a brand new, empty WordPress plugin and paste the above code inside.