Thaw scallops, if frozen. Scrub mussels under cold running water; remove beards and discard. Soak the mussels in cold salted water for 15 minutes, then drain and rinse. Repeat soaking, draining, and rinsing twice more. Set aside.

In a large saucepan bring the 1 cup water just to boiling. Place asparagus in saucepan and cook, covered, about 3 minutes or until crisp-tender. (Do not overcook.) Remove asparagus, reserving water in saucepan. Rinse asparagus in cold water; cover and chill in the refrigerator. Meanwhile, return water just to boiling. Add mussels to water and simmer, covered, for 5 minutes or until shells open. (Discard any mussels that do not open.) Drain and rinse mussels; cover and chill in the refrigerator at least 2 hours.

Heat oil in nonstick skillet. Cook scallops in hot oil for 1 to 3 minutes or until scallops are opaque; remove scallops; cover and chill in the refrigerator at least 2 hours. In a small bowl combine sour cream, lime peel, lime juice, 1 teaspoon of the roe or caviar, and the pepper. Cover and chill in the refrigerator.

Arrange chilled mussels, scallops, and asparagus on leaves of lettuce. Serve with sour cream mixture and remaining roe or caviar. Garnish salad with chives and lime wedges. Makes 2 servings.

Up to 24 hours ahead, cook the asparagus, mussels, and scallops. Cover and chill. Prepare the dressing. Cover and chill.