Place each cucumber between two chopsticks running horizontally. Slice into ⅛ to ¼-inch pieces not cutting all the way through. Flip the cucumber over and cut a second time on the diagonal using the same method. Repeat for the remaining cucumbers.
Place the cut cucumbers in a bowl with 1 tablespoon of vinegar and 1 teaspoon salt. Let this sit for 30 minutes, then drain in a colander to remove the excess water.
In a small bowl, combine the garlic, soy sauce, gochugaru, remaining vinegar, sesame oil, and sugar. Mix to combine.
Pour the mixture over the cucumbers and stir. The salad is ready to serve.