Line a large baking sheet with parchment paper. Combine cornstarch, juices and water in a small bowl.
Place cherries, 1/2 cup sugar, almond extract and salt in a medium pot. Cook and occasionally stir the mixture over medium heat until the sugar melts and the cherries just soften and their juices release. Mix in the cornstarch mixture, return to a simmer, and simmer until thickened, about 1 minute. Remove from heat and let cherries cool to room temperature.
Cut the puff pastry widthwise half. Set a half piece of pastry on a lightly floured surface. Roll that pastry into a 10” x 10” square. Now cut that square into 4, 5” x 5” squares.
Brush edges of each square lightly with egg wash. Now set 3 Tbsp. of the cherry mixture in a row in the centre of each square. Fold dough over the filling on each square, and then crimp edges with a fork to seal. Set the hand pies on the baking sheet, spacing them about 2” apart. Roll and fill the second half piece of dough as you did the first.
Brush the top of the pies lightly with egg wash, and then sprinkle with the 2 tsp. sugar. Cut 2 small slits in the centre, top of each pie to allow steam to vent. Refrigerate and chill the pies 30 minutes.
Preheat oven to 375°F. Bake the hand pies until golden brown, about 30 to 35 minutes, and then let cool on a baking rack.