For the sauce, in a small bowl stir together teriyaki sauce, vinegar, sesame oil, red pepper flakes, and salt and pepper to taste; set aside.
In a large skillet heat oil over medium-high heat. Add bell peppers; cook and stir 4 minutes or until crisp-tender. Add scallops and ginger; cook and stir 2 minutes. Add green onions; cook 1 minute or until scallops are opaque and firm. Stir in sauce; cook 1 minute. Spoon rice into 4 individual bowls. Spoon scallop mixture over rice. Sprinkle with sesame seeds, if desired, and serve.