Nutrition per serving may change if servings are adjusted.
2 medium zucchini, trimmed (about 7 oz. each)
2 teaspoons lime juice
¼ teaspoon chili powder
¼ teaspoon salt
Position racks in upper and lower thirds of oven; preheat to 225°F. Line 2 large baking sheets with parchment paper.
Slice zucchini ⅛ inch thick (a mandoline slicer is useful for this). Arrange the slices in a single layer on the prepared pans and pat dry with paper towels. (The slices should not overlap, but it's OK if they're very close together.) Coat lightly with cooking spray. Sprinkle with lime juice, chili powder, and salt.
Bake for 1 hour, switching the positions of the pans halfway through. Turn the zucchini slices over and continue baking until golden and no longer damp, 45 to 55 minutes more. (After the first hour, check every 5 to 10 minutes and remove any darker slices as they are done.) Transfer the zucchini chips to a wire rack to cool.
To make ahead: Store in an airtight container for up to 1 day. If chips lose their crunch, spread on a baking sheet and toast briefly in a toaster oven to crisp.
72 calories;4 g fat(0 g sat); 2 g fiber; 8 g carbohydrates; 2 g protein; 48 mcg folate; 0 mg cholesterol; 5 g sugars; 0 g added sugars; 499 IU vitamin A; 37 mg vitamin C; 34 mg calcium; 1 mg iron; 319 mg sodium; 530 mg potassium