Slice the zucchini. (Using a mandolin helps keep the slices consistent.) Lay the zucchini slices on paper towels in a single layer. Cover with more paper towels and set a baking sheet on top of the zucchini slices. Press down on the baking sheet, applying slight pressure, to help squeeze out some of the moisture.
Preheat the oven to 235 degrees F. (Preheat two ovens if you have them to fit more in at once.) Line several baking sheets with parchment paper. Brush the parchment paper lightly with olive oil.
Lay the zucchini slices in a single layer on the parchment paper. Fit as many on each baking sheet as possible. Then lightly brush the top of the zucchini with olive oil. Sprinkle the zucchini slices with salt. You can also sprinkle with a little cumin and smoked paprika for extra flavor.
Bake for 1 1/2 - 2 hours until crisp and golden. If some zucchini chips are still a little flimsy or damp, remove the crisp chips and place the damp chips back in the oven for a few more minutes. Allow the zucchini chips to cool on the paper towels to absorb any extra oil. Store in an air-tight container.