Arrange scallops in a steamer basket over boiling water. Cover, and steam 5 to 7 minutes or until done. Place in a shallow dish; drizzle with lime juice. Cover and chill.
Process watercress and next 5 ingredients in a food processor or blender until smooth; chill.
Arrange mixed salad greens on individual serving plates; top evenly with scallops and watercress mixture.
NOTE: Our test kitchen staff liked the watercress mixture so much, they recommed doubling it.