Press each rectangle into 7 1/2x5-inch rectangle. Cut rectangle into 3 rows by 2 rows to make 6 (2 1/2-inch) squares. Top each dough square with slightly rounded measuring teaspoon feta cheese mixture. Fold dough over filling, forming triangle; press edges to seal. On ungreased baking sheets, place triangles 2 inches apart. Repeat with remaining 3 dough rectangles and feta cheese mixture.