1. Pre-heat grill to medium high, and place grate at least 4 inches above fire.
2. In food processor, combine 1 mango, 1 C pineapple, sesame oil, lime juice and zest and lemon pepper. Process until smooth, and set aside in small bowl.
3. Combine lemon juice and sugar in a large bowl and stir until dissolved. Add scallops and toss to coat. Cover and refrigerate for at least 15 minutes.
4. Thread four scallops per skewer with the remaining mango (cut into 1/2-inch pieces), pineapple and pepper, alternating evenly.
5. Grill about four minutes on each side, until scallops turn opaque and have a bit of char to them. Transfer to a platter or individual plates and drizzle with sauce.