Prepare 2 squid bodies by removing the skin. Use coarse salt or a dry cloth if necessary. Cut the squid into halves and blanch in boiling water for 1 minute. Let cool in a colander without rinsing, then slice into bite-sized pieces.

Thinly slice perilla leaves and cucumber. Slice the onion and soak in cold water to remove its sharpness, then drain thoroughly.

Mix 2 tbsp gochujang, 4 tbsp vinegar, and 2 tbsp corn syrup in a bowl to create the dressing.