Squeeze skins in a paper towel to remove as much moisture as possible.
Spread skins on an unlined dehydrator tray and pulp on one lined with parchment. If using an oven, spread on lined baking sheets.
Turn your dehydrator to 135°F/57°C. For oven-drying, place the sheets in the middle of the oven and set it to 180°F/82°C. Rotate dehydrator racks or baking sheets every 30 minutes. Remove the skins when they're papery and the pulp when it's completely dry.
Let cool completely on the counter until room temperature. Transfer to a blender or food processor and blend on HIGH until powdered. Store in an air-tight container.