Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper. Carefully remove the skin from the salmon fillets. Cut the fish into 1” strips and set in a single layer on the baking sheet. Combine the remaining ingredients for the fish in a small bowl; brush over the fish. Bake for 8 to 10 minutes, or until just cooked through. While the fish cooks, heat the 1 Tbsp. oil in a large non-stick skillet set over medium-high. Add the red onion and bell peppers and cook until just tender, about 3 to 4 minutes. Set the cooked salmon, onions and peppers, salsa, lettuce, cheese and tortillas out on the table and allow diners to create their own fajitas.