Preheat oven to 400F. Heat a heavy nonstick skillet over medium high heat. Cook ground beef 4-5 minutes, stirring frequently, until browned. Stir in pepper and onion. Cook 3-4 minutes or until beef is no longer pink and vegetables are crisp-tender. Season with salt and pepper to taste. Place pizza crust on baking sheet. Remove beef and vegetables from skillet with a slotted spoon. Arrange on top of crust. Sprinkle with cheese. Bake 8-10 minutes or until cheese melts. Cut into wedges.