Wash the cucumbers under cold water. Peel if desired and slice into thin rounds. Set aside in a large bowl.

Slice the red onion thinly and shred the carrot. Add to the bowl with the cucumbers.

In a small bowl, combine rice vinegar, sugar, minced garlic, salt, and red chili flakes. Whisk until the sugar dissolves.

Pour the dressing over the cucumber mixture and gently toss to coat all ingredients.

Let the salad sit at room temperature for about 10 minutes to allow flavors to meld.

Chop the cilantro and sprinkle over the salad, then add crushed peanuts and give a final toss.

Optionally, chill the salad in the refrigerator for 15-20 minutes before serving.