Cook the egg noodles according to package instructions. Drain and rinse under cold running water. Transfer the noodles to a large bowl.
In a small bowl, whisk together the vinegar, oil, soy sauce, sesame seeds, ginger, salt, scallion, and, if using, red pepper. Remove the noodles from the refrigerator and mix with the sesame mixture until well coated. Serve cold or at room temperature.