This folding technique produces a two-pointed shape. It is the most suitable for boiled or steamed or soup wontons because there is maximal overlap of the layers of wonton skin, which helps keep them from going mushy.
For all wonton folds you start by placing the square of wonton skin on a flat surface (such as a small dish) and putting a round 1/2 teaspoon dollop of filling in the center, perhaps a bit towards corner A:
Now moisten your index finger with cold water and trace a streak above the filling, along the arc G-H-I in the diagram.
For the leaf shape, you place corner A directly over corner F, folding along the C-E diagonal. This gives you a right triangle shape:
Press firmly around the top of the filling (around the moistened arc you made before folding) to seal in the filling, eliminating as much air as possible. Turn the wonton so that the long edge (hypotenuse, for the mathematically inclined) is at the bottom.
For the second fold, bring the A-B edge halfway towards the right-angle apex (to the C-D line in the diagram). Your wonton will now look something like this:
Place a dab of cold water at point C. You're now ready for the third and final fold. Bring points A and B together so that they form a second point below the filling. Point B goes over point A, so that you can press the points firmly together and the moisture you dabbed at C forms a seal that holds A and B together during the cooking process.
Your wonton is now ready for cooking. Placing the finished wontons under a moist towel helps keep them from drying out as you fold them.
-Paul W.