In a small pan, heat your oil over medium heat until shimmering but not smoking, about 350°F (177°C).
In a large heat proof bowl, combine your green onion, garlic, chili flakes, dark soy, regular soy, MSG, sugar, Chinese black vinegar. Stir to combine. Carefully pour your hot oil over the chili flake mixture. Whisk until incorporated and set to the side.
In a large pot of boiling water, cook your noodles according to package directions, or until al dente, around 3-5 minutes. Drain the noodles then add to the bowl with the sauce. Toss the noodles to ensure they are evenly coated with the chili oil mixture.
Divide the noodles into bowls and top with your thinly sliced green onions. Serve and enjoy!