1. In a bowl or baking dish large enough to hold the meat, combine 1 tablespoon of sesame oil, 1 tablespoon of soy sauce, and the cornstarch and stir until mixed thoroughly. Add the meat to the marinade and toss to coat well. Cover with plastic wrap and set aside at room temperature for 20 to 30 minutes.
2. Meanwhile, bring a large pot of salted water to a boil and cook the noodles according to package directions or just done. Drain and toss with the remaining tablespoon sesame oil to keep from sticking together. Use a kitchen scissors to snip noodles into smaller pieces; set aside.
3. Combine the remaining 1 tablespoon soy sauce, rice vinegar, and sugar in a small bowl and mix well; reserve.
4. When ready to cook, set a wok or large skillet over medium-high heat and add the peanut oil. When the oil is almost smoking, add the garlic and ginger and stir-fry for 10 to 15 seconds or until fragrant. Add the red pepper, beef, and any marinade to the pan and continue to stir-fry for 2 to 3 minutes or until the meat is browned and of desired doneness. Add the celery and stir-fry 1 to 2 minutes more or until it turns bright green and is crisp-tender.
5. Add the reserved sauce and toss to coat well. Serve over noodles and garnish with cilantro and mint.