In a large bowl, combine the rice vinegar, soy sauce, sesame oil, sugar, salt, red pepper flakes, minced garlic, and grated ginger. Whisk until combined and the sugar is dissolved.
Add the sliced cucumbers to the bowl and gently toss, until the dressing is distributed evenly. [We use a mandolin to thinly slice the cumbers.]
Let the salad sit for at 10-15 minutes in the refrigerator, allowing the flavors to incorporate.
Right before serving, sprinkle the salad with sesame seeds, green onions, and finely chopped peanuts. Toss to combine.
Chill and serve!
Notes
Use a cucumber that has a thinner skin and is seedless. For example, the English cucumber does not need to be peeled.Optional to leave out the red pepper flakes according to your preference for heat.