Slice the zucchini into thin, even ⅛-inch rounds using a mandoline slicer.
Lay the zucchini slices in a single layer over paper towels.
Sprinkle lightly with kosher salt.
Cover with another layer of paper towels.
Place a baking sheet over the top and weigh it down with a cutting board or plate.
Allow the zucchini to rest for 15–20 minutes to release excess moisture.
Bake the Chips
Preheat the oven to 245°F (118°C).
Line one or two large baking sheets with parchment paper.
Lightly brush the parchment paper with olive oil.
Arrange the zucchini slices in a single layer without overlapping.
Brush the tops lightly with olive oil.
Sprinkle with harissa spice blend and additional salt if desired.
Bake for 1½ to 2 hours.
Check periodically and remove any chips that have already crisped.
Continue baking remaining slices until all chips are golden and crisp.
Allow the chips to cool slightly.
Serve warm or at room temperature alongside tzatziki sauce.