Safely meaning save the granite?

Or keep from getting physically hurt?

It is going to be glued on to what ever is under it---concrete board or sheet rock. What kind of glue will be the $64,000 question.

Basically, a couple of flat pry bars and muscle.

Back splash [3"-4" high] or wall splash?

back splash is probably just attached with adh. caulk or silicon. Pry up/out gently.
wall splash, ahhhh, I don't know. Same thing I guess?

Do you need to "save" the wall behind?
If not, cut the drywall out with the backsplash-and remove the drywall from the granite later.
Will have to patch the wall when finished.

We were able to do this by using a long thin knife and once the caulking was removed from the top of the granite, we used long sawing motions to cut through the adhesive on the back. The backsplash panels came off nicely and clean. I was able to rub the caulking off from the wall and back of the granite. Only problem was the blister I created on my pointer finger from all the rubbing..:0)