Cook noodles according to package directions, then drain.
Place the scallions, grated ginger, grated garlic, crushed red pepper flakes, and sesame seeds in a large heatproof bowl.
Place light neutral oil in a small saucepan, then heat over high heat until it begins to smoke. When very hot, pour the oil over the sauce ingredients, then stir well.
To the same bowl, add soy sauce, chili crunch oil, rice wine vinegar, brown sugar, and fish sauce. Stir until thoroughly mixed.
Add the cooked noodles, toss well, then taste and adjust seasoning, as needed. Divide between two bowls, then garnish with fresh cilantro and sesame seeds. Serve with fresh lime wedges and an extra drizzle of chili oil, if desired.