In a large skillet cook ground beef until brown. Drain off fat. Stir in the water, chile peppers, taco seasoning mix, and chili powder. Bring to boiling; reduce heat. Simmer, uncovered, 15 to 20 minutes or 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 F oven for 5 minutes.
In a small bowl mash pinto beans with a fork. Spread beans over partially baked dough to within 1/2 inch of edges. Spoon meat mixture over beans. Bake, uncovered, 10 minutes more or until crust is just golden. Sprinkle with the cheese. Bake 1 to 2 minutes more or until cheese is melted. Top with lettuce, tomato, and green onions. If desired, serve with taco sauce. Makes 6 servings.