Crumble the ground beef into a 1 1/2 quart casserole dish. Cover with glass lid. Cook in the microwave for 5 minutes on High. Drain, and stir in chili powder, salt, garlic powder, cayenne pepper and water. Cover and return to the microwave. Cook for another 3 to 4 minutes on High.
Fill each taco shell with about 2 tablespoons of the ground beef, then top with desired amounts of cheese, lettuce, onion, tomato and taco sauce.
