In fact, the most proper way to do this is to use removeView. To remove the parent layout, you can check whether there’s a top parent view. However, you need to know the ID of at least one of the currently initialized views.
But I would suggest you reinitialize the existing layout in webix.ui call rather than deleting+creating the new one: http://webix.com/snippet/ac5648a4
Also, please note that if you need to use these views multiple times, a multiview can make a switch between views more comprehensive (without unnecessary layout rebuilding).