Sprinkle each tortilla lightly with water and stack them on a plate. Cover the top with another plate turned upside down and microwave the tortillas for 1 minute or until warm. Turn two 12 cup muffin pans upside down. Mist each side of a tortilla lightly with cooking spray and center it in the space between 4 muffin cups, creating a bowl. Repeat with the 5 remaining tortillas, forming 3 bowls on each tin. Bake in the oven for 8-10 minutes.
While the tortilla bowls are baking, spray a large skillet with cooking spray and add the ground beef and brown. Add 1/3 cup water and taco seasoning, bring to a boil and then reduce heat to simmer 3-4 minutes.
Let the tortilla bowls cool for a few minutes after removing them from the oven. In each bowl, layer 1/4 cup meat, 1 TBSP cheese, 1 TSP taco sauce, 4 quarters of grape tomato and some shredded lettuce.