Wash the cucumbers thoroughly and peel them partially using a peeler for texture. Slice them into bite-sized pieces and sprinkle with salt to let them sit for a while. Slice the onion thinly.

Prepare the seasoning sauce by mixing gochujang, red pepper flakes, minced garlic, sugar, soy sauce, corn syrup, vinegar, sesame oil, and sesame seeds.

Squeeze the salted cucumbers to remove excess water. Place them in a bowl along with the sliced onions.