Begin by washing the cucumbers thoroughly. Smash each cucumber using a rolling pin or chef's knife until they split.

In a medium bowl, combine rice vinegar, salt, and red chili flakes. Whisk for about 30 seconds until the salt almost dissolves.

Add the smashed cucumbers to the dressing bowl and toss gently until well coated.

Cover the bowl and let the salad marinate at room temperature for at least 10-15 minutes.

Taste the salad, adjust seasoning if needed, and garnish with cilantro or green onions before serving.