Add cold water little by little and mix everything together with a spoon (or your hands), until the mixture begins to come together and a soft dough is made. You can add more water if required.
Turn the dough onto the counter and knead for 5-6 minutes using the heels of your hands. Kneading helps to form gluten and makes the dough smooth and elastic. This is a very important step to getting perfect wonton sheets.
Lightly dust your countertop with cornstarch (NOT flour), and roll as thin as you can into a rough rectangle. Thick wrappers produce an overly doughy result that can overwhelm the filling.
Dust the wrappers generously with cornstarch to stop them from sticking to each other. Stack them and wrap them in cling film. Keep the covered stacks in a ziplock bag and freeze until ready to use.
Repeat with the remaining dough.
Thaw the wrappers overnight (or 2-3 hours) in the fridge before using them.
You can also cut these into rounds for dumplings.