Preheat oven to 425F. Grease a large baking sheet with 1 tablespoon oil. Set aside.
In a large bowl, combine ground chicken, cabbage, carrots, pepper, onion, garlic, ginger, soy sauce, salt, and red pepper flakes.
Fill a small bowl with water. Place dumpling wrappers on a work surface and place about 1 tablespoon filling in the center of each wrapper (just under a tablespoon fits best!) Use your fingers to rub the edges of each wrapper with water, then fold the dough over filling to create a half-circle. Pinch edges to seal.
Arrange potstickers in a single layer on prepared baking sheet. Brush potstickers with remaining 1 tablespoon oil.
Bake potstickers at 425F 10 minutes, then remove from oven and carefully flip each potsticker to opposite side. Return to oven and continue baking an additional 10-12 minutes until potstickers are golden and register 165F on a thermometer inserted in center of one. Keep potstickers warm for serving.