For sauce: In a small mixing bowl, whisk together all sauce ingredients. Set aside.
For filling: In a large mixing bowl, combine ground pork, shrimp, sesame oil, ginger, garlic, green onion, salt and pepper. Mix together until everything I evenly combined.
In a small bowl combine egg and 1 tablespoon water. Whisk together.
Brush the edge of a wonton wrapper with egg wash and fill the center with 1 ½ tablespoons filling.
Fold dumpling in half, making sure to get rid of any air pockets before completely sealing. You should have a half circle at this point. Dip one corner of dumpling in egg wash. Bring both corners into the center of dumpling and seal together.
Repeat steps 4 and 5 until all filling and wrappers have been used.
Place a pot of water over high heat and top with a bamboo steamer. Line steamer with a steamer liner or leaves of green cabbage.
Add a few dumplings to the steamer about ½ inch apart. Cover and once water is boiling, steam dumpling for 7 to 9 minutes or until dumplings have cooked through completely. Transfer dumplings to a shallow bowl and repeat.
To serve: Drizzle sauce over steamed dumplings and serve with more sauce on the side.