For filling, in a large bowl combine tofu, mushrooms, green onions, water chestnuts, hoisin sauce, chili sauce, and soy sauce. Spoon about 1 tablespoon of the filling into the center of each wonton wrapper. Brush edges of wrapper with water. Fold one corner of wrapper to opposite corner to form a triangle; press edges to seal.
Lightly coat large baking sheets with cooking spray. Place the wonton triangles on prepared baking sheets. Lightly coat the triangles with cooking spray. Bake in a 400 degrees oven about 10 minutes or until triangles are crisp and golden brown. Drain on paper towels. If desired, serve the hot triangles with teriyaki sauce.