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

In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the ground beef and cook until browned, breaking it apart with a spatula, about 5-7 minutes. Drain excess fat if necessary.

Add the red bell pepper, snap peas, garlic, and ginger to the skillet. Stir-fry for about 3-4 minutes until the vegetables are tender-crisp.

In a small bowl, whisk together the soy sauce, hoisin sauce, sriracha, sesame oil, rice vinegar, and sugar. Pour this sauce over the beef and vegetable mixture, stirring to combine. Cook for an additional 2 minutes.

Add the cooked rice noodles to the skillet, tossing everything together until the noodles are heated through and well-coated with the sauce.

Serve hot, garnished with chopped green onions and sesame seeds if desired.