To prepare salmon, combine the first 6 ingredients in a large skillet; bring to a boil. Add fish to pan. Cover, reduce heat, and simmer 10 minutes (fish may not be completely cooked). Remove from heat. Let stand, covered, 10 minutes. Remove fish from pan with a slotted spoon; place on a dish. Cover and chill. Discard cooking liquid.
To prepare sauce, combine mayonnaise and next 9 ingredients (through pepper) in a small bowl; cover and chill.
Cook peas in boiling water 1 minute or until crisp-tender. Drain and rinse with cold water; drain. Arrange 2 cups of lettuce and 3/4 cup peas on each of 4 plates. Top each serving with 1 salmon fillet and about 3 tablespoons sauce.