Wonton Soup

Shell and devein shrimp. Rinse and pat dry with paper towel. Use a cleaver to chop shrimp into a fine paste. Combine shrimp paste with remaining filling ingredients in a large bowl. Mix well.
Place 1 wonton skin on a flat surface with corners at top, bottom, left and right. Place about 1 teaspoon filling in bottom corner of wonton skin. Fold bottom corner over filling and roll up, stopping 1 inch from top corner. Press down on each side of the filling to seal. Dab egg yolk on right side of the filling. Fold sides under filling, leaving corners free. Press to seal. Repeat with remaining wonton skins and filling. Any remaining filling may be frozen. As each wonton is assembled, place on a large plate under a dry towel.
Bring 8 cups water to a boil in a large pot. Carefully lower each wonton into boiling water with a slotted metal spoon. Stir gently to prevent wontons from sticking to bottom of pot or each other. Bring to a second boil. Add 1 cup cold water and bring to a third boil. Wontons will float when done. Carefully remove each wonton with slotted spoon and set aside.
Pour chicken broth and 5 cups water into a pot. Bring to a boil over high heat. Reduce heat to medium and cook 5 minutes. Add sesame oil, salt, pepper, green onions and barbequed pork (if using). Carefully lower cooked wontons into soup and serve at once.