Prepare the sauce by finely chopping onion, green chili, red chili, and garlic. Mix sugar, soy sauce, vinegar, and water until sugar dissolves. Add the chopped vegetables and stir well.

Boil 1 liter of water with 1 tsp salt and a dash of vinegar. Add somen noodles and stir occasionally to prevent sticking.

When the water boils, add cold water to reduce the temperature. Repeat this process 3 times until noodles are cooked. Drain and rinse noodles under cold water.

Place the rinsed noodles in ice water to untangle them, then drain and shape into small bundles.