In a nonstick 10-inch saute pan, cook the turkey bacon over medium-high heat until crisp. Transfer bacon to paper towels to drain grease and set aside. When bacon has cooled, break each piece in half.
In a large bowl, combine ground turkey, watercress, Worcestershire sauce, mushrooms, and pepper and stir until well mixed. Form meat mixture into 4 patties.
Heat a nonstick griddle or large nonstick pan over medium-high heat and spray twice lightly with canola oil cooking spray. Place each patty on griddle, in batches as necessary, and cook for about 3 to 5 minutes. Flip burgers, cook for another 3 to 5 minutes, and then top each patty with 1 slice of bacon (which will be in 2 pieces), and 1 slice of cheese. Cook until cheese is has softened. Remove patties from griddle. Spread 1/2 tablespoon of light mayonnaise over each English muffin half. Place burgers on 1 half English muffin and top the burger with 1 slice of tomato, 1 slice of red onion, and 1/4 cup of shredded lettuce.