1Combine ground beef and green pepper in a 1 1/2 quart glass casserole, cover. Microwave on high for 6 minutes, stirring once. Stir in tomato paste and seasonings, cover. Microwave on high for 6 to 9 minutes, or until mixture bubbles, stirring once. Let stand, covered 5 minutes. Divide beef mixture between taco shells. Top first with shredded cheese, then with tomato, onion, and lettuce.