Heat oven to 375°F. Coat baking sheet with vegetable cooking spray. In bowl, combine pecans, sugar, and cinnamon.
On lightly floured surface, unfold piecrust and roll into 12-inch circle. Brush piecrust with water. Spread nut mixture over circle. Using pizza cutter, divide circle into 16 wedge-shaped slices.
Starting at curved side of each slice, roll to form crescent. Place 1 inch apart on prepared baking sheet. Bake 20 to 25 minutes, or until golden brown.