In a bowl, mix ground chicken, minced garlic, grated ginger, diced scallions, sesame oil, rice vinegar, soy sauce, salt, & pepper. Make the gyoza sauce.
Spoon 1 tablespoon of filling into center of each wrapper. Brush edge of wrappers with water.
Fold top edge of wrapper over filling to meet bottom edge of wrapper, creating a half-moon shape. Pinch edges tightly to seal.
Heat avocado oil over med heat. Add gyoza to skillet in a single layer. Work in batches if needed.
Cook on one side until golden brown.
Flip gyoza & repeat on other side. Remove from heat & serve with gyoza sauce.