PreparationFor sauce: Mix all ingredients in bowl. (Can be made 1 week ahead. Cover; chill. Bring to room temperature before using.) For vegetables: Mix first 4 ingredients in large bowl. Add watercress, cucumber, carrot, cilantro, and onion and toss to blend. Season with salt and pepper. Let stand 30 minutes or chill up to 1 hour, tossing occasionally. For scallops: Stir coriander seeds in small skillet over medium heat until fragrant and slightly darker, about 2 minutes. Transfer seeds to plastic bag. Using mallet or hammer, coarsely crack seeds. Combine sesame oil and ginger in medium bowl; mix in coriander seeds, then scallops. Let stand at least 30 minutes or chill up to 1 hour. Prepare barbecue (medium-high heat). Thread 3 scallops onto each of 4 skewers. Brush barbecue rack with oil to prevent sticking. Grill scallops until just opaque in center, about 3 minutes per side. Divide vegetables among 4 plates. Top each with scallops and serve, passing hoisin-orange sauce separately. Available at Asian markets and many supermarkets.
PreparationFor sauce: Mix all ingredients in bowl. (Can be made 1 week ahead. Cover; chill. Bring to room temperature before using.) For vegetables: Mix first 4 ingredients in large bowl. Add watercress, cucumber, carrot, cilantro, and onion and toss to blend. Season with salt and pepper. Let stand 30 minutes or chill up to 1 hour, tossing occasionally. For scallops: Stir coriander seeds in small skillet over medium heat until fragrant and slightly darker, about 2 minutes. Transfer seeds to plastic bag. Using mallet or hammer, coarsely crack seeds. Combine sesame oil and ginger in medium bowl; mix in coriander seeds, then scallops. Let stand at least 30 minutes or chill up to 1 hour. Prepare barbecue (medium-high heat). Thread 3 scallops onto each of 4 skewers. Brush barbecue rack with oil to prevent sticking. Grill scallops until just opaque in center, about 3 minutes per side. Divide vegetables among 4 plates. Top each with scallops and serve, passing hoisin-orange sauce separately. Available at Asian markets and many supermarkets.