1Prepare the sauce by combining gochujang, gochugaru, soy sauce, sesame oil, sugar, minced garlic, rice vinegar, and half of the sesame seeds in a mixing bowl. Stir until well combined and the sugar is dissolved. Set aside.
2Bring a large pot of water to a rolling boil. Add the somen noodles and cook according to package instructions, typically 2-3 minutes, until al dente. Stir occasionally to prevent sticking.