1. Combine mayonnaise, lemon zest, juice and cayenne. Set aside.
2. Cook bacon in a nonstick skillet on medium heat until brown and crisp. Remove and drain on paper towels. Pour off all fat and wipe skillet clean. Add oil.
3. Cook salmon in skillet on medium-high heat 2 to 3 minutes per side or until translucent.
4. Spread 4 slices of the bread with mayonnaise mixture. Layer 1 lettuce leaf, 2 slices tomato, 1 salmon fillet and 1 piece bacon on top of each. Cover with second slice of bread. Cut in half and serve.
Nutritional information per serving: Calories 430; Total Fat 23g; Saturated Fat 6g; Tran Fat 0; Cholesterol 66mg; Sodium 670mg; Total Carbohydrate 28g; Dietary Fiber 5g; Total Sugars 6g; Protein 27g
Variation: Use cooked flaked salmon for a cold sandwich.