Rinse the cucumbers well and slice them thinly into rounds or half-moons as preferred.
Transfer the sliced cucumbers to a sizable bowl, sprinkle with salt, and stir to combine. Let them rest for around 10 minutes to draw out moisture.
While the cucumbers rest, mix rice vinegar, soy sauce, chili flakes, sugar, sesame oil, and minced garlic (if using) in a small bowl until the sugar dissolves.
After the cucumbers have released liquid, drain and rinse them under cold water to lessen the saltiness. Then, gently pat dry using a clean towel.
Put the cucumbers back in the bowl and pour the dressing over them. Toss everything together so all slices are coated evenly.
Sprinkle the chopped green onions and sesame seeds over the salad and give it one more gentle toss to incorporate.
Place the salad in the fridge and let it chill for about 20 minutes before serving to allow the flavors to fully blend.
