Bring 2 cups water to a boil, add the couscous and stir. Cover and turn the flame off. Allow to couscous to steam for 5 minutes. Remove and fluff with a fork to cool. Add the vegetables, garbanzo beans and pistachios. Mix thoroughly.
To prepare the dressing, place umeboshi paste, tahini, scallions and water in a blender. Puree until creamy. Serve over the salad.
Per serving - 449 calories, 7 g fat (14% calories from fat), 17 g protein, 79 g carbohydrate, 7 g fiber, 0 mg cholesterol, 250 mg sodium