Cook ground beef in a large skillet over medium-high heat until browned. Drain, if necessary.
Stir in diced tomatoes then add chili powder, cumin, salt and pepper. Stir to combine.
While the beef cooks, spray 12 muffin cups with cooking spray. Line each muffin cup with two wonton wrappers. Fill each cup with 3 tablespoons of cooked beef mixture. Top each cup with 1 tablespoon cheese.
Bake at 375F for 10-13 minutes or until wontons are golden brown and cheese has melted. Top with your favorite toppings.