Combine ground pork, chopped Napa cabbage, sliced green onions, minced garlic, grated ginger, soy sauce, and sesame oil in a mixing bowl.
Stir the mixture thoroughly until all ingredients are evenly combined and the filling becomes sticky and cohesive.
Place a gyoza wrapper on your palm, then spoon a small amount of filling (about a teaspoon) into the center of the wrapper.
Dip your finger in water and run it along the edge of the wrapper to moisten it.
Fold the wrapper in half over the filling, pinching the edges together to seal and creating pleats if desired for a traditional look.
Repeat the filling and folding process with the remaining wrappers and filling, arranging the assembled gyoza on a tray or plate without stacking.
Heat vegetable oil in a non-stick skillet over medium-high heat until shimmering and slightly fragrant.
Place the gyoza flat-side down in the hot oil, making sure not to overcrowd the pan. Fry until the bottoms are golden and crispy, about 2-3 minutes.
Pour water into the pan and immediately cover with a lid, trapping the steam. Reduce heat to medium and let steam for 3-4 minutes, until the filling is cooked through and the wrappers are tender.
Remove the lid and cook for another minute to let the bottoms crisp up again. Listen for the crackling sound and watch for golden edges.
Transfer the gyoza to a serving plate and serve hot with dipping sauce. Enjoy the crispy, tender bites with their savory filling.