Keep them away from the computer you use to sync the ipad. You can always put them back as long as they are in your itunes. Deletion is only permanent then and only after emptying the trash or recycle bin.
I have all my granddaughter's apps on one page, I hand it to her open to that page, and if she were to delete, she will go without and knows it! She also can only use it while I am sitting nearby.