On a lightly floured surface, unfold piecrust according to package directions. Cut into four wedges.
For each wedge, spoon about 2 tablespoons of desired pie filling in the center of the wedge, and top with about 1 tablespoon chopped pear or apple.
Moisten edges of pastry with a little water. Fold pastry over fruit to form another triangle. Press edge of pastry with tines of fork to seal.
Prick top of tart with tines of fork. Place on an ungreased cookie sheet and bake in a 375 degree F oven about 20 minutes or until pastry is golden brown. Serve warm or cool. Makes 4 tarts.