Japanese Gyoza Dumplings

Name: Japanese Gyoza Dumplings
Ingredients: 1 pound napa cabbage ((about 5 cups, roughly chopped into large pieces)); 8 ounces ground pork ((70% to 80% lean)); 1 clove garlic ((smashed)); 1 1/2 teaspoons fresh ginger ((minced)); 1 scallion ((chopped)); 2 tablespoons vegetable oil ((plus more for pan-frying)); 1/2 teaspoon sesame oil; 2 teaspoons soy sauce; 3/4 teaspoon sugar; 1/2 teaspoon salt; 1/8 tsp white pepper; Store-bought gyoza wrappers; 2 tablespoons soy sauce; 1 teaspoon rice vinegar; 1 tablespoon hot water; 1 teaspoon sugar