Prep the pork: Freeze the pork for 15 minutes to firm it up, then slice against the grain into thin strips.
Toss with a pinch of salt, black pepper, and half the cornstarch. This helps the pork sear and stay tender.
Make the sauce: In a small bowl, mix soy sauce, oyster sauce, hoisin (if using), dark soy (if using), rice vinegar, sugar, remaining cornstarch, and 2 tablespoons of water. Stir until smooth.
Cook the noodles: Boil noodles until just shy of done (al dente).
Drain and rinse briefly under cool water to stop cooking. Toss with a little oil to prevent sticking and set aside.
Heat the pan: Place a large wok or skillet over high heat. Add 1 tablespoon of oil and swirl to coat until shimmering.
Stir-fry the pork: Add pork in a single layer.
Let it sear for 60–90 seconds without moving, then stir-fry until just cooked through. Remove to a plate. Do not crowd the pan; cook in batches if needed.
Aromatics: Add another tablespoon of oil.
Add garlic, ginger, and the white parts of the scallions. Stir-fry for 20–30 seconds until fragrant.
Veggies: Add onion and bell pepper; cook 2 minutes. Add snap peas and cabbage; cook another 2–3 minutes until crisp-tender.
Season lightly with salt and pepper.
Combine: Return pork and any juices to the pan. Add noodles and pour in the sauce. Toss vigorously over high heat for 1–2 minutes until the sauce thickens and coats everything.
Finish: Turn off the heat.
Drizzle with sesame oil, add the green parts of the scallions, and sprinkle red pepper flakes if you like heat. Taste and adjust seasoning.
Serve: Plate immediately. Garnish with sesame seeds and lime wedges for a fresh pop.