Preheat 7 cups of oil in a deep fryer to 350 degrees. You could also use a heavy skillet and fry in small batches. For a healthier version, broil the chicken in the oven.
Mix the pepper sauce and water in a bowl. Combine the flour, salt, cayenne pepper, black pepper, onion powder, paprika and garlic powder in a different bowl.
Pound each of the chicken pieces until about 3/8-inch thick. Trim if necessary to help it fit on the bun. For easy cleanup, place the chicken in a zip bag before pounding.
Coat each piece with the flour, then roll it in the watered down pepper sauce. Coat the chicken again in the flour mixture and set it aside. Repeat for other fillets.
Fry the chicken for 10 minutes or until they are brown and crispy. Remove the chicken to paper towels to drain.
Prepare each sandwich by grilling the face of the hamburger buns on a hot fry pan. Spread 2 teaspoons of mayonnaise on each bun. Place a tomato slice on the mayonnaise, then stack lettuce on top of the tomato.
On the bottom bun, place one piece of chicken. Assemble and serve warm.