Combine flour and salt in a bowl. Gradually add warm water while mixing until a rough dough forms. Add sesame oil and knead for 10 minutes until smooth. Cover and rest for 30 minutes.
After resting, divide dough into pieces and roll or stretch into long strands by pulling evenly until thin. Dust lightly with flour to prevent sticking.
Boil noodles for 2–3 minutes until tender. Drain and set aside.
In a wok or large pan, heat oil over medium-high heat. Add garlic, then chicken, snow peas, carrots, mushrooms, and green onions. Stir-fry for 3–4 minutes.
Add soy sauce, oyster sauce, chicken stock, and pepper flakes. Toss to combine.
Add the cooked noodles last, tossing thoroughly to coat with sauce. Cook for another minute and serve hot.