Step 1: Prepare the Filling : In a large bowl, combine the ground pork, chopped cabbage, green onions, garlic, and ginger. Add soy sauce, sesame oil, rice vinegar, sugar, white pepper, and cornstarch. Mix everything thoroughly with your hands or a spoon until well combined and slightly sticky. Cover and refrigerate for 15 minutes to let the flavors blend.
Step 2: Fill and Fold the Gyoza : Place a gyoza wrapper on your palm. Spoon about 1 teaspoon of pork filling into the center. Dip your fingertip in water and wet the edge of the wrapper. Fold the wrapper in half over the filling and pleat one side while sealing the edges firmly. Tip: Aim for 4–5 small pleats per dumpling. Repeat until all wrappers are filled. Keep finished gyoza covered with a damp towel to prevent drying out.
Step 3: Pan-Fry the Gyoza : Heat 1 tablespoon of oil in a large non-stick skillet over medium-high heat. Arrange 10–12 dumplings in a single layer (flat side down). Fry for 2–3 minutes until the bottoms are golden brown. Carefully pour in ¼ cup of water and immediately cover with a lid. Steam for 4–5 minutes, or until the water evaporates and the wrappers are tender. Remove the lid and let them fry again for 1–2 minutes to crisp up the bottoms. Repeat with remaining gyoza.
Step 4: Make the Dipping Sauce : In a small bowl, whisk together soy sauce, rice vinegar, sesame oil, chili oil (if using), and sugar. Sprinkle with green onions or sesame seeds if desired.