Thaw pastry for 20 minutes. In a large skillet, brown beef. Add salsa, taco seasoning and water. Bring to a boil and then simmer for 5 minutes.
Add cheese; remove mixture from the heat.
Preheat oven to 400 degrees.
On a floured surface roll pastry to a 15-inch square. Cut pastry into 25 3-in squares. Place 1 rounded tablespoon beef mixture into the center of each square. Fold pastry over to form a triangle. Seal edges and brush with egg wash. Sprinkle with chili powder.
Place on ungreased baking sheets and bake for 10 minutes or until golden.