01 - Combine the sliced beef with 1 tablespoon soy sauce, cornstarch, and 1 teaspoon sesame oil in a bowl. Mix thoroughly and let it marinate for 10 minutes.
02 - Cook noodles following package instructions. Drain, rinse under cold water, and set aside.
03 - Whisk together soy sauce, oyster sauce, chili garlic sauce, rice vinegar, brown sugar, and toasted sesame oil in a small bowl until combined.
04 - Heat a large wok or skillet over high heat and add 1 tablespoon vegetable oil. Stir-fry the marinated beef in batches until just browned, about 2 minutes per batch. Remove and set aside.
05 - Add more oil if necessary to the wok. Stir-fry minced garlic and grated ginger for 30 seconds until aromatic. Add bell pepper, carrot, and sugar snap peas, stir-frying for 2 to 3 minutes until just tender.
06 - Return cooked beef to the wok, add noodles and pour in the sauce. Toss everything together and heat through for about 2 minutes.
07 - Stir in sliced spring onions gently.
08 - Serve immediately, garnished with sesame seeds, fresh cilantro leaves, and extra spring onions.