Halve 1 English cucumber lengthwise, then cut diagonally into thin slices. Add ¼ cup of thinly sliced onion, 1 scallion, chopped, and 2 garlic cloves, minced.
Add 2 tablespoons of soy sauce, 2 teaspoons of gochugaru, 2 teaspoons of toasted sesame oil, 2 teaspoons of toasted sesame seeds, and 1 teaspoon of sugar.
Toss until evenly coated and the sugar dissolves. Serve immediately.
