Lightly coat a 12- to 13-inch pizza pan with nonstick cooking spray. Pat dough evenly into prepared pan, building up edges slightly. (If dough is hard to pat out, allow to rest for 10 minutes.) Prick crust all over with a fork. Bake in a 425 degrees oven for 12 minutes.
Meanwhile, in a large skillet cook the ground beef and onion until meat is brown and onion is tender. Drain off fat. Stir in the 2/3 cup salsa. Top partially baked crust with meat mixture. Bake for 5 minutes more. Sprinkle with tomatoes and cheese. Bake for 2 to 3 minutes more or until cheese melts.
To serve, top with lettuce and tortilla chips. If desired, serve with sour cream and/or additional salsa.
For a Stuffed Crust Pizza:Lightly coat a 12- to 13-inch pizza pan with nonstick cooking spray. Pat dough evenly into prepared pan, extending edges over pan slightly. (If dough is hard to pat out, allow to rest for 10 minutes.) Sprinkle 2 ounces shredded cheese in a thin strip around the edge of the dough. Moisten edge of dough. Fold down edge over cheese and seal tightly to enclose the cheese. Prick crust all over with a fork. Bake as above.
Per Serving: cal. (kcal) 279, Fat, total (g) 9, chol. (mg) 35, sat. fat (g) 3, carb. (g) 33, Monosaturated fat (g) 3, Polyunsaturated fat (g) 0, fiber (g) 3, sugar (g) 2, pro. (g) 18, vit. A (IU) 583.08, vit. C (mg) 5.9, Thiamin (mg) 0.04, Riboflavin (mg) 0.12, Niacin (mg) 2.37, Pyridoxine (Vit. B6) (mg) 0.25, Folate (µg) 16.13, Cobalamin (Vit. B12) (µg) 1.04, sodium (mg) 500, Potassium (mg) 304, calcium (mg) 80.77, iron (mg) 1.44, Percent Daily Values are based on a 2,000 calorie diet