Prepare the Salad: Thinly slice the cucumbers and red onion, then place them in a large mixing bowl. Add the chopped cilantro, mint leaves, and sliced chili peppers (if using).

Make the Dressing: In a small bowl, whisk together rice vinegar, fish sauce, lime juice, sugar, sesame oil, and minced garlic. Stir until the sugar dissolves completely.

Combine the Ingredients: Pour the dressing over the cucumber mixture. Carefully mix the vegetables and herbs, ensuring that each piece is lightly coated with the dressing.

Let It Chill: For the best flavor, let the salad sit in the refrigerator for 10–15 minutes to allow the dressing to meld with the ingredients.

Serve and Garnish: Just before serving, sprinkle crushed roasted peanuts over the top for added crunch and garnish with a few extra mint or cilantro leaves if desired. Serve chilled as a side dish or appetizer.