Preheat the oven to 400 degrees. In a small bowl combine dried minced onion, chili powder, cornstarch, garlic powder, cumin, oregano, and cayenne pepper. Mix well and set aside.
In a large skillet brown ground beef over medium-high heat. Drain off any excess liquid. Add refried beans, tomato sauce, and prepared taco seasoning. Mix well.
Spoon the taco meat mixture into the taco shells and place into a 9 x 13 inch baking dish, standing up. Sprinkle cheese over the top of the taco meat in each shell. Place into the oven and bake at 400 degrees for 10-12 minutes or until the cheese has melted and the tacos are heated through. Remove from the oven and top with any optional condiments for serving.