In a small bowl combine the tomato paste, coconut aminos, white vinegar, and Stevia. Set aside.
Season the pork with the sea salt, black pepper, and garlic powder. Sprinkle the flour over the pork. Place the pork in a 4- to 6-quart slow cooker.
Add the onion, pineapple, and bell peppers. Pour the chicken broth and coconut aminos mixture into the slow cooker and stir to combine. Cover and cook on LOW for 8 hours. Serve topped with the green onions and sesame seeds, if desired.