Add the all-purpose flour and salt to a mixing bowl. Whisk to combine.
Add the egg and cold water. Whisk until the batter is completely smooth, thin, and almost runny, similar to thin pancake batter.
Place a non-stick pan over low-medium heat. Coat it lightly with cooking spray.
Add just enough batter to coat the bottom of the pan. Use a pastry brush or silicone spatula to quickly paint it into a thin, even layer.
Cook until the wrapper no longer looks wet and the edges begin to curl away from the pan.
Carefully flip the wrapper. Cook the second side for 40 to 45 seconds.
Transfer the wrapper to a plate. Repeat with the remaining batter, spraying the pan lightly again only as needed.
Keep the finished wrappers covered until you are ready to fill them.