Beat the cream cheese and butter until smooth and fluffy. Add the flour and salt and mix just until a soft dough forms.Divide into 2 disks, wrap, and refrigerate at least 2 hours.Heat the oven to 375°F. Roll one disk ⅛ inch thick on a lightly floured surface. Cut into 2-inch squares.Place ½ teaspoon filling diagonally in the center of each square.Fold one corner over the filling, dab with water, then fold the opposite corner over and press firmly to seal.Place on lined sheets and bake 12 to 15 minutes until the bottoms are lightly golden.Cool completely, then dust with powdered sugar.