1. To make the marinade: Place all the ingredients in a medium nonaluminum bowl. Whisk just until combined. Taste & adjust the seasonings. 2. In a large saucepan, combine the water, wine & bay leaf over medium-high heat. Bring to a boil. Add the shrimp. Cover & cook, stirring occasionally, for 3 to 4 minutes, or until the shrimp are pink on the outside & just cooked in the center. 3. Remove the shrimp with a slotted spoon to a deep bowl or large rectangular plastic container. Return the cooking liquid to a boil, add the scallops & cook for 2 to 3 minutes, or until the center of each scallop is opaque. 4. Remove the scallops with the slotted spoon & add to the shrimp. 5. Add the red & yellow bell peppers, onion, olives, lemon (if using) & parsley to the seafood. Pour in the marinade & stir well to combine the ingredients & to coat the seafood. Refrigerate for at least 4 hours or up to overnight, stirring the seafood occasionally to marinate evenly. 6. To serve: Arrange the lettuce on a large platter & using a slotted spoon, top with the seafood mixture. Drizzle a little of the marinade over the seafood. Serve with small plates & forks or toothpicks. Or, serve on individual plates as a first course. Advance Preparation: Make up to 1 day ahead through step 5. Cover & refrigerate. Remove from the refrigerator 15 minutes before serving.