Trim the end off the cucumber and fit it into the spiralizer. Twist the cucumber through the spiralizer until it has been transformed into a frenzy of cucumber springs.

Toss the cucumber slices with the salt and sugar and let sit for 15-20 minutes. Drain away any liquid that gathered in the bottom of the bowl.

Add the vinegar, oil, and red onion and toss to combine.

Just before serving, top with the toasted sesame seeds, if using.