Boil the buckwheat noodles in boiling water and rinse them in cold water.
Thinly slice the toppings such as cucumber and seaweed flakes.
Place the cooked noodles in a bowl and mix with perilla oil, soy sauce, vinegar, and sugar.
Top with garnishes (cucumber, seaweed flakes, sesame seeds, etc.).
Add chili powder or garlic to taste.