Bring a large pot of water to a boil. Separate napa cabbage leaves and blanch for 1–2 minutes until pliable. Pat dry or let drain and set aside.
In a large bowl, combine ground chicken, garlic, ginger, green onions, soy sauce, sesame oil, salt, pepper, and optional gochugaru. Mix well until fully combined.
Lay a cabbage leaf flat. Add a spoonful of filling near the thicker white stem. Roll just enough to cover the filling, fold the sides inward, then continue rolling tightly like a burrito to fully seal. Place finished dumplings seam-side down.
Steam dumplings seam-side down for 15 minutes until fully cooked, OR pan-fry seam-side down in neutral oil over medium heat for 4–5 minutes, flip and cook another 4–5 minutes, then increase heat to medium-high and cook 1–2 minutes more, turning to crisp all sides.
Serve warm with your favorite dipping sauce.
