Gather your supplies. I didn't have enough shallots on hand so added some red onion.
Wash, dry and trim cucumbers. Use a vegetable peeler to remove alternating strips of the peel.
Cut the cucumbers in half crosswise and then again into thin slices. Note I used regular cucumbers with seeds this time and it was just as good! Place in a non reactive bowl.
Peel the shallots and cut into very thin slices and add to the cucumbers.
Whisk together the vinegar, sugar, and salt in a liquid measuring cup until the sugar has dissolved.
Pour the vinegar mixture over the cucumber and shallot mixture. Mix well, separating the slices.
Cover tightly and refrigerate for at least 3 hours. Taste and adjust the seasoning as needed before serving.