Begin by slicing the Persian cucumbers thinly—aim for about ¼-inch slices. Place the slices in a colander and sprinkle them generously with salt; let the cucumbers sit for 10 minutes.

After 10 minutes, gently blot the cucumber slices with paper towels to remove excess moisture.

In a small microwave-safe bowl, combine the rice vinegar and sugar, stirring until the sugar starts to dissolve. Microwave on high for about 30 seconds.

In a large mixing bowl, combine the dry cucumber slices with thinly sliced red onion. Pour the prepared dressing over and gently toss.

Cover the mixing bowl with plastic wrap or a lid and refrigerate for at least 20 minutes.

Just before serving, remove the salad from the refrigerator, toss gently, and top with fresh cilantro and crushed peanuts.