Start cooking the clams for a minute before adding the shrimp so both will be done at the same time.
Bring 1 cup water to a boil in a large saucepan. Add clams; cover and cook 1 minute. Add shrimp; cover and cook 3 minutes or until shrimp are done and clam shells open. Drain; discard any unopened clam shells.
Combine mayonnaise, lime juice, and wasabi, stirring with a whisk. Place 2 cups greens on each of 4 salad plates; divide clams and shrimp evenly over greens. Drizzle each serving with about 1 tablespoon wasabi mixture; sprinkle each serving with 1 tablespoon cilantro.