Blend ¼ teaspoon kosher salt, 1 tablespoon lime juice, and 2 tablespoons olive oil. Toss gently with 1 pound cooked shrimp, lobster dice, or lump crabmeat. Arrange Bibb lettuce leaves on four plates. Mix seafood gently with salsa and spoon over lettuce or mound salsa on lettuce, then arrange seafood on top. Garnish with basil sprigs.