Add salt to the cucumber, mix well and set aside in the fridge for 10-15 minutes. In the meantime, make the Dressing, by combining all the ingredients in a small sauce pan. Turn on the heat and reduce the Dressing a bit so it’s slightly thickened. Let cool.
Drain the salt water from the cucumber completely. Toss the cucumber, onion, and mix with the Dressing. Top with the peanut and cilantro, serve immediately