Cook the noodles according to package instructions, then drain and set aside.
Heat olive oil in a large pan over medium heat.
Add sliced onion and cook for 2–3 minutes until soft.
Add mixed vegetables and sauté for 4–5 minutes until slightly tender.
In a small bowl, mix soy sauce, honey, sesame oil, black pepper, and chili flakes.
Add the cooked noodles to the pan and pour the sauce over them.
Toss everything together for 2–3 minutes until well coated and heated through.
Remove from heat and sprinkle with sesame seeds if desired.