For Peanut Dressing: Whisk together all ingredients. Refrigerate until ready to use.
For each serving: Toss 1 cup spaghetti with 1/2 cup cabbage, 1/4 cup carrots, 1/4 cup celery, 1 Tbsp. peppers and 2 Tbsp. Peanut Dressing. Top with 1 tsp. each peanuts, scallions and cilantro.