Heat oven to 375°F. Line large cookie sheet with cooking parchment paper. In 2-quart saucepan, mix strawberries, rhubarb, 1/2 cup sugar, the cornstarch and orange peel. Cook over medium heat 6 to 8 minutes, stirring constantly, until bubbly and thickened. Cool slightly.
Remove pie crusts from pouches; unroll on work surface. With 2 1/2-inch round cookie cutter, cut 14 rounds from each crust; reroll scraps. On cookie sheet, place half of the dough rounds 2 inches apart. Top each with 2 teaspoons fruit mixture. Brush crust edges with water; top with remaining dough rounds. Press edges firmly with fork to seal. Cut slits in top of each round.
In small bowl, beat egg yolk and whipping cream; brush over tops of pies. Sprinkle with 2 teaspoons sugar.
Bake 20 to 25 minutes or until lightly browned. Serve warm or cool.