In a large mixing bowl, combine the ground pork, shredded napa cabbage, minced green onion, grated ginger, half of the minced garlic, half of the coconut aminos, sea salt, and black pepper.
Mix the pork filling vigorously with a spoon or clean hands until the mixture becomes slightly sticky and well incorporated.
Place a dumpling wrapper on a flat surface and spoon roughly 1.5 tablespoons of the pork mixture into the center of each.
Wet the edges of the wrapper with a small amount of water, fold in half, and pinch the edges tightly to create a seal, pleating if desired.
Heat the avocado oil in a large non-stick skillet over medium-high heat and arrange the dumplings in a single layer.
Cook the dumplings for 2 to 3 minutes until the bottoms are deeply golden and crispy.
Carefully pour 3 tablespoons of water into the skillet and immediately cover with a tight-fitting lid to steam for 5 minutes.
While the dumplings steam, whisk together the remaining coconut aminos, toasted sesame oil, rice vinegar, remaining garlic, and chili flakes in a small dipping bowl.
Remove the lid from the skillet and continue cooking for 1 more minute to allow any excess moisture to evaporate and the bottoms to re-crisp.
Transfer the hot dumplings to a plate and serve immediately alongside the spicy chili-garlic dipping sauce.