Slice your citrus as thinly as you can (this is where using a mandoline comes in handy). 1-2 millimeters thick is ideal. Discard the ends.
Arrange your slices in one layer in the basket of your air fryer and set inside. It’s okay if your slices touch - they just shouldn’t overlap.
Select the “dehydrate” setting, and make sure you oven is set to the highest convection setting. Set the temperature to 175 degrees and the time to 2 hours and 30 minutes. You’ll know the citrus is ready when the pulp is transparent, with an appearance like stained glass!
Once cooled, store your dried citrus in an airtight container. It should last at least 2 years.