Cut the cucumbers in half lengthwise, and then thinly slice crosswise slightly diagonally. If the cucumbers are thin, you can simply cut into thin rounds.
Heat a pan over high heat. Add oil to the pan. Quickly stir in the garlic. Add the cucumbers. Stir-fry for a minute until the cucumbers are slightly cooked. Toss well with the scallion, sesame oil, and sesame seeds.