You can't. I've seen shops that highlighted all their listings and meant to deactivate them and instead accidentally hit delete. They had to start over from scratch.
When you do hit delete you get this pop-up that you have to confirm:
Keep in mind that deleted listings can’t be retrieved. If you’d like to keep a listing from being viewed publicly without deleting it permanently, please deactivate the listing instead. This will allow you to edit or reactivate it at any time.
