Prepare the cucumber by washing it very well then slicing it thinly. Place the slices on a towel (or paper towels) to remove as much moisture as possible.
Make the dressing by combing the rice vinegar, toasted sesame oil, soy sauce, honey, and salt together in a small jar. Seal with a lid and shake well. Side Note: We like a tangy dressing, so if you don't, use a bit less vinegar.
Pour the dressing over the cucumber slices and toss to coat evenly. Place into the refrigerator for 30-60 minutes, tossing occasionally.
To serve, sprinkle the salad with toasted sesame seeds, black sesame seeds, and crushed red pepper flakes, if desired. Serve and enjoy.
Side Note: This salad can be made up to 3 hours ahead of serving, but for best results should be served the day it's made.