Heat avocado oil in a large skillet over medium-high heat.
Add the chopped onion to the skillet and sauté until translucent, about 3-4 minutes.
Stir in the minced garlic and grated ginger, and cook for an additional minute, until fragrant.
Add the ground chicken to the skillet, breaking it up with a spatula. Cook until the chicken is browned and no longer pink, about 5-7 minutes.
While the chicken is cooking, in a small bowl, whisk together soy sauce or coconut aminos, sesame oil, apple cider vinegar, and red pepper flakes if using. Set aside.
Once the chicken is cooked, add the shredded cabbage to the skillet. Cook, stirring frequently, until the cabbage is tender-crisp, about 5 minutes.
Pour the ginger sauce over the chicken and cabbage mixture, tossing to coat evenly. Season with salt and pepper to taste.
Cook for another 2-3 minutes, allowing the flavors to meld together.
Remove from heat and transfer to serving dishes.
Garnish with sliced green onions and a sprinkle of sesame seeds before serving.