Prep the cucumbers. Using a sharp knife or a mandolin, cut the cucumbers into thin slices. Place the sliced cucumbers in a salad bowl.
Combine. To the cucumbers, add cilantro, minced jalapeno, and green onions; gently toss to combine.
Make the salad dressing. In a separate mixing bowl, whisk together rice vinegar, sesame oil, sugar, and salt.
Put it all together. Pour the dressing over the cucumbers and gently toss to combine. Taste for salt and adjust. Top the sesame cucumber salad with pepper flakes, basil, and sesame seeds, and serve.