Place the zucchini slices in a single layer on paper towel for about 20 minutes so they dry out a bit. Pat off any excess moisture, then place the slices in a large bowl. Toss with 2 tablespoons of oil and season with salt and pepper.
Preheat the oven to 250 degrees. Lightly oil a baking sheet (or two, depending how many slices your zucchinis yield) or use cooking spray. Place the zucchini slices in a single layer on the sheets.
Bake for 2 to 2½ hours, checking regularly to make sure they’re cooking evenly, until the chips are crisp.