Cook the noodles according to package instructions until al dente. Drain and reserve about ¼ cup of cooking water.

In a bowl, whisk together gochujang, soy sauce, sesame oil, honey (or maple syrup), minced garlic, and rice vinegar if using. Add reserved cooking water to loosen the sauce.

Heat 2 tablespoons of vegetable oil in a small skillet over medium heat. Swirl in the sesame seeds and scallion whites, frying gently until golden and fragrant—about 1–2 minutes—then transfer to a paper towel to drain; this becomes the crispy sesame crunch.

In the same skillet, pour in the gochujang‑sesame sauce and warm gently over low heat for 1 minute.

Add the cooked noodles to the skillet, tossing thoroughly to coat evenly in sauce. Add a splash of reserved pasta water as needed to achieve desired sauciness.

Transfer noodles to serving bowls and sprinkle the crispy sesame-scallion mixture over the top. Garnish with the green parts of the scallions and red pepper flakes if desired.

Taste and adjust salt or sweetness if necessary. Serve immediately.