Cook the Noodles: Boil noodles according to package instructions until just al dente. Drain and toss with 1 tsp sesame oil to prevent sticking. Set aside.
Make the Sauce: In a small bowl, whisk soy sauce, oyster sauce, hoisin, sesame oil, sugar, garlic, ginger, and cornstarch slurry until smooth. Set aside.
Prepare the Shrimp: Pat shrimp dry with paper towels and season lightly with salt and pepper.
Cook the Shrimp: Heat 1 tbsp oil in a large wok or skillet over medium-high heat. Add shrimp and stir-fry 2–3 minutes until pink and opaque. Remove and set aside.
Stir-Fry the Vegetables: Add another 1 tbsp oil to the same pan. Toss in onion, bell pepper, cabbage, and snap peas. Stir-fry for 3–4 minutes until crisp-tender.
Combine Everything: Return shrimp to the pan. Add cooked noodles and pour the sauce over. Toss everything together with tongs until noodles are coated and sauce thickens slightly (2–3 minutes).
Finish u0026 Garnish: Sprinkle with green onions and sesame seeds before serving.