Adjust oven racks to upper-middle and lower-middle positions and heat oven to 375°F. Line two large, rimmed baking sheets with parchment paper or aluminum foil and spray lightly with nonstick spray.
If using store-bought pie dough, set it on the counter 15 minutes before using.
In a large bowl, mix together cream cheese, Queso Fresco, chili powder, cumin, red pepper flakes, Pepper Jack and scallions with an electric mixer on medium speed. Add chicken and mix until incorporated; set aside.
Unroll the dough and use a rolling pin to create a 12” round. With a 4” round cookie cutter, cut the dough into 7 (4-inch) rounds per pie crust.
Make an egg wash by whisking 1 egg with 1-teaspoon water.
To Make the Empanadas:
Brush the edges of the dough rounds with egg wash.
Place 1 rounded tablespoon of chicken filling in the middle of each pastry round and fold the dough over to form a half-moon empanada. Press the filling down a little to bring the dough together.
Brush each empanada with egg wash.
Press the edges of the dough together and then use a table fork, to crimp the edges to seal.
Lightly sprinkle the empanadas with flake sea salt, if desired.
Place the empanadas, 1-2 inches apart on the prepared baking sheets.
Make 3 tiny slits in the top of each empanada to release steam.
See *Note if making ahead.
Place a tray on the upper-middle oven rack and the lower-middle oven rack. Bake at 375°F for 20-22 minutes switching and rotating baking sheets halfway through baking. Cool a few minutes then serve with avocado slices and Apple-Jicama Slaw (or just the Honey-Chipotle Vinaigrette).
Note for making ahead: The empanadas may be made up to two days ahead. Cover the uncooked empanadas, on the baking sheets, with plastic wrap and refrigerate. Add 5-7 minutes cooking time when baking.