Finely mince or grate the garlic, then finely chop the green onions. Save the whites to add into the chili oil at the end, and save the greens as a garnish on top of the noodles at the end. Set them both aside for later.
Boil the noodles as per the package instructions, subtracting 1 minute from the suggested time for a more al dente and chewy noodle. Once cooked, drain and set aside.
In a small pot, set the stove to medium-low heat and add in the garlic, neutral oil, Sichuan chili flakes, Chinkiang vinegar, sugar, and soy sauce. Cook this mixture for about 3 minutes to allow the flavors to meld together, stirring to prevent burning.
Once the chili oil has finished cooking, turn off the heat and add in the whites of the green onions, toasted sesame oil, and sesame seeds, mixing everything together.
Add the noodles back into the pot with the chili oil and mix until all the noodles are well coated. Garnish with the greens of the green onions and enjoy!
