Mushi Gyoza Steamed Gyoza

Name: Mushi-Gyoza (Steamed Gyoza)
Ingredients: 1 pound ground pork; 1 cup dried shitake mushrooms, rehydrated and chopped fine; 1 tablespoon green onion, chopped fine; 1 tablespoon ginger, grated; 2 cloves garlic, crushed; 2 teaspoons corn starch; 1 teaspoon salt; 1 teaspoon sugar; 1 tablespoon mirin; 1 tablespoon soy sauce; 3 tablespoons canola oil; 1 tablespoon sesame oil; 50 round gyoza wrappers; 3/4 cups soy sauce; 1/3 cup vinegar; 2 Thai chili peppers, chopped with seeds