To Make Ahead: Prepare the dressing in advance and store it in an airtight jar in the refrigerator for up to a week. When ready to serve, smash the cucumbers, toss them in the dressing, let them marinate briefly, and garnish as instructed.
To Store: Keep any leftover salad in an airtight container in the refrigerator for up to three days. For optimal texture, add the toasted sesame seeds and green onions just before serving.