In a small bowl, combine all the ingredients for the dumplings (except for the wrappers and milk) and mix with your hands or large spoon until well combined.
Lay 9 to 12 wonton wrappers on a work surface and place about half a teaspoon of stuffing right in the center of each wrapper. Brush the edges with a little bit of milk and then fold the wrappers in half, bringing one corner slightly passed the center of the opposing edge (see picture in post for visual reference). Press to seal, taking care to remove as much air as you can.
Brush a little bit more milk on both sides of the edges of the folded wontons and then crimp the edge "accordion" style to form a little purse, pressing lightly as you go to ensure that they stick well.
Repeat with the rest of the wonton wrappers until you run out of stuffing.
Be sure to keep the wrappers and finished dumplings covered with a damp cloth while you are working to ensure that they don't dry out.
Once all the dumplings are done, you can choose to cook them immediately or refrigerate or freeze them in airtight containers to cook at a later time; just make certain that they do not touch until completely refrigerated or frozen to prevent them from sticking together. Refrigerated dumplings will keep for maximum of 24 hours, while the frozen ones will keep for up to several months. You can cook the frozen dumplings directly from the freezer without thawing them first.
To make the sauce
Combine all the ingredients in a small saucepan and bring to a simmer over medium-low heat, whisking constantly, until smooth and creamy. Note that you can make the sauce while the dumplings are cooking.
To cook the dumplings
Bring plenty of salted water to a roaring boil; Delicately add the dumplings to the boiling water and boil until fully cooked, about 2 to 3 minutes for fresh dumplings, 6 to 8 minutes for frozen.
Remove the cooked dumplings with a slotted spoon, letting excess water drip, and place them in a large serving plate or shallow bowl. Pour the sauce directly over the dumplings, garnish with toasted sesame seeds and serve without delay.