To make the Barbecue Sauce:
1. Heat the avocado oil in a saucepan over medium heat.
2. Add the onion and cook for 2 minutes.
3. Add the tomato paste and cook, for 2 minutes more, stirring constantly.
4. Stir in the remaining ingredients, and simmer until the sauce is slightly thickened, for approximately 5 minutes.
To make the Barbecue Chicken:
1. Preheat the oven to 425°F.
2. Place a wire rack over a rimmed baking sheet.
3. In a large bowl, combine the chicken, avocado oil and ¼ cup of the barbecue sauce.
4. Toss to coat and place on the rack.
5. Bake, using a brush to baste with the remaining ½ cup sauce every 10 minutes, until the chicken is cooked through, for about 30 minutes.