Remove Dashboard Widgets

// Remove Dashboard Widgets
function remove_dashboard_widgets() {
	global $wp_meta_boxes;
	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins']);
	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_recent_drafts']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_comments']);
	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']);
	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary']);
   }
if (!current_user_can('manage_options')) {
	add_action('wp_dashboard_setup', 'remove_dashboard_widgets');
}

Source: 10+ Useful WordPress Code Snippets