You can order it with varying degrees of spicyness, but every kung pao I've seen has dried chili peppers as a key ingredient along with garlic.
When I order Kung Pao chicken (or shrimp, etc.) it comes with onion, celery, and sometimes water chestnuts as the vegies. It always comes with peanuts, but I see no reason you couldn't order it without.
I make it at home without peanuts since we have peanut allergies and don't eat at Chinese (or Thai,etc.) restaurants as a family for that reason.
At home, the sauce I make is pretty much cooking sherry and cornstarch. The spice comes from the garlic and the peppers. I toss some grated ginger in sometimes as well. We like lots of peppers for flavor, but push them to the side rather than eating them to avoid the heat.