Put the cucumbers in a small strainer and sprinkle them with ½ teaspoon of salt. Let them sit for 5 minutes to draw out some moisture while you make the dressing.
In the bottom of a large bowl, vigorously whisk together the dressing ingredients until well combined. Whisk in a teaspoon of hot water at a time until you get the right consistency. The dressing should be just pourable and not gloppy. Set aside.
Very lightly press and squeeze the cucumbers and then lightly dry them with a paper towel to remove the excess moisture and salt.
Place the cucumbers and remaining salad ingredients in the large bowl on top of the dressing. Toss to combine.
Right before serving, toss again and garnish with sesame seeds. Serve immediately at room temperature or refrigerate for up to 2 hours before serving.
Notes
Store leftover cucumber salad in an airtight container for up to 3 days. The texture of the cucumbers will become soggier and less crisp, and the dressing more watery the longer it is stored. I prefer to eat mine fresh or the next day.The dressing could be made up to 3 days in advance, just make the dressing in a small bowl, but don't add in the hot water. Store it covered in the fridge. When ready to serve, place the made ahead dressing base into the bottom of the serving bowl and add the hot water like you would in step 2.