Preheat oven to 375-degrees F.
Brown ground beef in skillet. Drain excess fat. Add salt.
In a small mixing bowl, combine tomato sauce, oregano, pepper, and garlic salt.
Arrange muffin halves on a baking sheet. Spread tomato mixture over each muffin half. Top tomato mixture with browned ground beef. Top beef with mozzarella and Parmesan cheeses.
Bake for 10 to 15 minutes or until cheese melts.
Nutritional information per two "pizza" serving: 323 calories (41% from fat), protein 18.7 g, fat 14.4 g (poly 1.1 g, mono 5.4 g, sat 6.3 g), carb 28.9 g, fiber half g, chol 52 mg, iron 2.9 mg, sodium 688 mg, calcium 197 mg.