Chop up the shrimp into small pieces and add to a large bowl along with the ground pork.
Use your hands to mix in the scallions, cilantro, fish sauce, salt, corn starch, egg, sesame oil, water chestnuts, and fresh ginger.
Form the meat mixture into balls about 1 inch (3 cm) round and place them on a baking sheet lined with parchment paper.
Brush a circle of water around the perimeter of a won ton wrapper and place a meatball in the center. Gather the edges up and press the wrapper against the meat making a tight little cylinder. Put on a baking sheet lined with parchment paper or dusted with corn starch. Repeat with remaining meatballs.
To steam the dumplings, line a Chinese bamboo steamer with parchment paper with a few holes poked in it. Turn on the heat, and once the steamer is hot, steam the dumplings until hot all the way through, which will take about 5 minutes. (You can also use a steamer basket lined with cheesecloth or parchment paper with a few holes poked in it.)
Mix all the dipping sauce ingredients together. Serve with the hot, steamed dumplings.