1. To prepare crust, weigh or lightly spoon flour into dry measuring cups; level with a knife. Combine 2 1/2 cups flour, salt, and 2 tablespoons sugar in a food processor; pulse 10 times. Add frozen butter, and process until mixture resembles coarse meal. Place food processor bowl and flour mixture in freezer for 15 minutes.
2. Place the bowl back on the processor. Combine vodka and cold water. Add the vodka mixture slowly through food chute, pulsing just until combined.
3. Divide dough into 12 equal portions. Shape each dough portion into a ball; flatten each ball into a 3-inch circle on a lightly floured surface. Roll each dough portion into a 5-inch circle, adding the remaining 1/4 cup flour as needed to prevent dough from sticking. Stack dough circles between single layers of wax paper or plastic wrap to prevent sticking. Cover stack with plastic wrap; refrigerate at least 2 hours or overnight.
4. To prepare filling, combine peaches, 1 cup water, orange juice, 3/4 cup sugar, and cinnamon in a medium saucepan. Bring to a simmer; cover and cook for 1 hour, stirring occasionally. Remove from heat, and mash with a potato masher; cool.
5. Preheat oven to 425°. Place a large foil-lined baking sheet in oven.
6. Remove dough from the refrigerator. Working with 1 circle at a time, spoon 2 level tablespoons peach mixture into center of each circle. Fold dough over filling; press edges together with a fork to seal.
7. Combine milk and egg in a small bowl, stirring with a whisk. Brush pies evenly with egg mixture. Cut three diagonal slits across top of each pie. Remove hot baking sheet from oven, and coat with cooking spray. Place pies, cut sides up, on baking sheet, and place on middle oven rack. Bake at 425° for 18 minutes or until lightly browned. Cool slightly on wire rack.