Step 1

Make the dressing. Combine the vinegar, salt, and sugar in a small mixing bowl. Stir until the salt and sugar dissolve.

Step 2

Prep the veggies. Cut the cucumber in half lengthwise, then use a spoon to scrape out the seeds. Cut into ¼ inch thin slices. Cut the onion into very thin slices.

Step 3

Combine and chill. Put the veggies in a mixing bowl and pour the dressing on top. Stir to combine, then cover and chill for at least 2 hours.