Heat oil in large skillet over medium high heat. Add the bean sprouts and cook quickly for 30 seconds. Add the peppers and stir fry. Add the scallions and stir. Remove vegetables to a strainer to drain.
In a large bowl, mix together vinegar, sugar, salt and sesame oil. Add vegetables and toss tocoat. Refrigerate for 6 hours before serving.
Recipe Courtesy of Food Network Kitchens