Line 2 baking sheets with silicone mats. Quarter 1 medium acorn squash and scoop out the seeds. Slice the squash quarters crosswise about 1/16 inch thick using a mandoline. Drizzle with olive oil and toss; arrange on the baking sheets in a single layer and sprinkle with salt. Bake at 250 degrees F, 50 minutes, rotating the baking sheets halfway through. Flip the slices and continue baking until browned, about 15 more minutes. Transfer the chips to a rack to cool.