Preheat your oven to 425°F. Line two large baking sheets with silicone baking mats and set them aside. (Parchment paper works if you don’t have silicone baking mats, but they cook much faster on parchment paper, so keep a very close eye on them. I also think the texture is slightly better when you use silicone baking mats.)
Wash and dry the zucchinis. Slice them into thin, even rounds, about 1/8-inch thick. You can use a mandoline slicer or a sharp knife for this step. Place the zucchini slices in a colander and sprinkle 2 teaspoons of salt over the slices and let them rest for about 30 minutes or until about 1/3 to 1/2 cup of water has drained from the chips. Rinse the zucchini under cool running water then lay the zucchini slices out on 2 layers of paper towels. Pat dry with another paper towel, then lay a paper towel on top of them. Let them rest for 20 minutes to allow the paper towel to absorb more moisture.
To a large mixing bowl, add the olive oil, garlic powder, onion powder, paprika, dried oregano, salt, and black pepper. Mix well.
Add the zucchini slices to the bowl and toss gently to coat them evenly with the oil and spice mixture.
Arrange the seasoned zucchini slices in a single layer on the prepared baking sheets, making sure they don't overlap.
Bake the zucchini chips in the preheated oven for 12 minutes. Then, carefully flip each zucchini slice, removing any crispy ones that are finished baking, and bake for an additional 5-8 minutes (checking them after 5 minutes), or until they are golden brown and crispy. These brown quickly, so keep a close eye on them when they’re baking on the second side.
Remove the baked zucchini chips from the oven and let them cool on the baking sheets for a few minutes. They will become even crispier as they cool.