Cook the rice noodles according to package instructions. Drain and set aside.

In a bowl, combine the sliced flank steak, soy sauce, oyster sauce, hoisin sauce, and cornstarch. Mix well and let marinate for 15 minutes.

Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Add the marinated beef and stir-fry for 3-4 minutes until browned. Remove the beef from the skillet and set aside.

In the same skillet, add the remaining tablespoon of oil. Sauté the garlic and ginger for about 30 seconds until fragrant.

Add the sliced red bell pepper and snap peas to the skillet. Stir-fry for 2-3 minutes until the vegetables are tender-crisp.

Return the beef to the skillet and add the cooked noodles. Toss everything together and stir-fry for another 2-3 minutes until heated through.

Garnish with sliced green onions and sesame seeds if desired. Serve hot.