01 - Bring a large pot of water to a rolling boil. Cook the noodles according to the package directions until just al dente. Drain the noodles, rinse briefly under cold running water, and set aside.
02 - Heat the neutral oil in a large skillet or wok over medium heat. Add the scallion strips and cook, stirring regularly, until the scallions turn deeply golden and crisp at the edges, approximately 7 to 10 minutes. Using tongs, transfer the crispy scallions to a plate, reserving the scallion oil in the pan.
03 - Reduce the heat to low. Carefully add the light soy sauce, dark soy sauce, sugar, and toasted sesame oil to the scallion-infused oil. Stir until the sugar dissolves and the sauce becomes aromatic, about 30 seconds.
04 - Add the drained noodles to the skillet. Toss thoroughly to ensure the noodles are evenly coated with the sauce and heated through, about 1 minute.
05 - Divide the noodles between serving bowls. Top with the reserved crispy scallions. Add chili oil and toasted sesame seeds as desired. Serve immediately.