In a small bowl, combine the mayo and capers. Refrigerate until ready to use.
Preheat the oven to 400 degrees F. (or preheat grill).
Place the salmon fillets on a pan, drizzle them with oil and sprinkle with salt and pepper. Bake 8 to 10 minutes, or just until cooked through (or grill the salmon!)
Meanwhile, butter the rolls and toast them under the broiler for a couple of minutes, or until golden.
Divide the caper mayo between the two rolls. Top each with lettuce, salmon, tomato slices and bacon. Serve!