Preheat grill to medium high. Season salmon with salt and pepper, lightly drizzle olive oil over salmon. Place salmon on hot grill, turning just once after 3 minutes, turn salmon over and allow to cook for an additional 3 minutes. Or until salmon is 145 degrees in the thickest point. Salmons should flake easily, but be careful not overcook.
Spread mayonnaise on 4 slices of bread, spread a spoonful of pesto if desired. Add lettuce, tomato and 2 slices of bacon and top with cooked salmon. Place plain sliced bread on top and enjoy! Repeat with remaining ingredients.
This is also a great open-faced sandwich option!