In a medium bowl, combine peppers, panko, garlic, and salmon.
In a small bowl, combine egg, soy sauce, and lemon juice; add to pepper mixture, tossing gently to combine. Form mixture into 4 patties.
Lightly coat grill with cooking spray. Heat over medium-high heat until hot. Grill patties, 5 minutes per side, or until desired degree of doneness. Top each with a lettuce leaf, tomato slice, and salmon patty. Cover with tops of buns.