Preheat oven to 400° F. Line a large baking sheet with parchment paper.
Lightly flour a clean rolling surface and roll a pie crust into a rectangle shape, roughly 11" x 15". Trim ends and sides as necessary to keep edges straight. Use a table knife and divide the crust in half, lengthwise. Then, divide each half widthwise.
In a small mixing bowl, combine pumpkin, brown sugar, pumpkin spice, and salt. Use a table fork to mix until smooth. Use a tablespoon and place a dollop of filling to half of the cut-outs. Spread evenly, staying ½" away from edges.
Place a cut-out without filling on it on top of one that has the filling. Use a table fork to crimp the edges. Next, apply a light egg wash to each pop tart and use a toothpick to poke ventilation holes in each top.
Repeat process with second pie crust.
Place in oven for about 20 minutes, until golden brown. Then, remove from oven and allow to cool on the baking sheet for 10 minutes. While the pop tarts are cooling, prepare the icing.
For the Pop Tart Icing
Use a small mixing bowl and combine powdered sugar, milk, and vanilla extract. Adjust sugar to milk ratio so the icing is not too thick but thin enough to spread.
Using a flat spatula, remove pop tarts from baking pan and place on wire cooling rack and allow them cool to room temperature. Then, apply an even coat of icing on each pop tart. Sprinkle on a layer of cinnamon sugar and garnish with optional fresh orange zest if desired.