Combine first 7 ingredients in a bowl, tossing to combine. Cover and chill 2 hours.
Drain and reserve juice from tomato mixture; set mixture and juice aside.
Thread scallops evenly onto wood skewers that have been soaked in water. Sprinkle with salt and pepper, and brush scallops with reserved juice.
Grill scallops, covered with grill lid, over medium-high heat (350° to 400°) 3 to 4 minutes on each side or just until scallops are opaque. Serve over cooked orzo, and top with reserved tomato mixture.