Very tasty and quite easy. Note: Do not put veggies on the whole pizza if you want to have leftovers...they get yucky when you try to re-heat. I also like to substitute pepper jack cheese for cheddar.
In large skillet cook meat until brown. Drain off fat. Stir in 3/4 cup water, chile peppers, taco seasoning mix, and chile powder.
Bring to boil; reduce heat. Simmer uncovered for 15-20 minutes (until most of the liquid is gone).
Meanwhile, grease a baking sheet and sprinkle with the cornmeal. Pat pizza dough into a 12x8-inch rectangle on the baking sheet. Bake in a 400 degree oven for 5 minutes.
In a bowl, mash beans with a fork; spread over partially baked dough to within 1/2 inch of the edges.
Spoon meat mixture over beans. Bake uncovered, 10 minutes more, or until crust is just golden.
Sprinkle with cheese. Bake 1-2 minutes more (until cheese melts).
Top with lettuce, tomato, and onion. If desired, serve with taco sauce.