In a small saucepan, measure and add the rice wine vinegar, sugar and salt. Bring to a boil, reduce to medium and simmer until syrupy. About 5 minutes.
Pour the vinegar syrup into a mixing bowl to cool.
Once cooled, add the cucumber, red onion slices and sambal oelek. Use tongs to toss to combine. Let the cucumber soak up the syrup for about 5 minutes. Then toss one more time before transfering to a serving dish.
Top with the chopped herbs and peanuts.
