Mix freshly roasted salmon with smoked salmon for a delicious filling that’s not overpowering. Bonus: The salmon mixture can be made up to 3 days in advance.
Heat oven to 450° F. Roast the salmon fillet on a rimmed baking sheet until cooked through, 6 to 8 minutes; let cool, then flake.
Combine the smoked salmon, mayonnaise, celery, chives, capers, lemon zest, flaked salmon, and ¼ teaspoon pepper in a medium bowl.
Divide the salmon salad and lettuce leaves among the bread.