Preheat the oven to 425 Degrees F. Line a baking pan with parchment paper. Set in the salmon. Drizzle fish with oil and lemon juice; season with salt and pepper or Cajun spice. Bake 12 to 15 minutes, or until cooked through. Spread buns with mayonnaise. Top bottom buns with lettuce, and then set on a salmon fillet, removing the skin first, if desired. Divide and top salmon with tomato, cucumber, onion and bell pepper. Set on top buns and serve.
Recipe Options: Instead of salmon, make the burgers with another type of fish fillet, such as halibut or snapper. Instead of lettuce, top the bottom buns with baby spinach or arugula. Instead of mayonnaise, spread the buns with store-bought or homemade tartar sauce. For a recipe to make the latter, see this website collection recipe: Baked Halibut Steaks with Homemade Tartar Sauce.