Begin by thoroughly washing the cucumbers, then slice them thinly using a sharp knife or mandoline for uniformity. Sprinkle the sliced cucumbers generously with salt, tossing them gently to ensure they are evenly coated. Allow them to sit for about 10 minutes.

While the cucumbers are resting, grab a medium-sized mixing bowl. Combine rice vinegar, soy sauce, chili flakes (or gochugaru), and sugar. Add sesame oil and whisk until the sugar is dissolved.

After 10 minutes, rinse cucumbers under cold water to remove excess salt and drain well. In a large mixing bowl, add the drained cucumbers to the dressing and toss until well-coated.

Sprinkle sesame seeds for added crunch and mix in finely chopped green onions and garlic if using. Toss gently to distribute garnishes.

Let the salad sit for at least 10 minutes before serving to allow flavors to meld. Chill for enhanced refreshment if desired.