Stir pumpkin puree, applesauce (if using), maple syrup (or honey), and pumpkin pie spice together in a bowl with a whisk or a fork until smooth.
Line dehydrator trays (or your baking sheet) with parchment paper. Drop rounded tablespoonfuls of pumpkin mixture on the parchment paper in ¼” thick round shapes like cookies.
Sprinkle a little coconut on top, optional.
Dry in a dehydrator set at 130°F (55°C) until completely dry. The amount of time this takes depends on your dehydrator. It could take 10-12 hours. If using the oven method, bake in a preheated oven at 175°F for 4-5 hours.
To test for doneness, pick up one piece and bend it. It should be dry and flexible, with no pockets of moisture. Remove the pieces that are dry and let them cool in an open bowl. Continue drying the remaining pieces of fruit leather until they, too, are done. It goes quicker at the end, so check those last few every 15 minutes.
Dust completely cooled pumpkin leather with cinnamon to keep it from sticking together, and store it in an airtight container.