6 (6-ounce) salmon fillets |
cooking spray |
1/2 cup chopped red onion |
1/3 cup fat-free mayonnaise |
1 tablespoon dijon mustard |
1 teaspoon chopped fresh dill |
1 teaspoon capers, drained |
1 teaspoon fresh lemon juice |
1/4 teaspoon salt |
1/8 teaspoon black pepper |
6 bibb lettuce leaves |