First, place the chicken in the buttermilk and marinate for 2 hours or overnight in the fridge.
Prepare the spice mix. In a small bowl, combine the smoked paprika, ground coriander, ground cumin, dried oregano, salt and chilli powder. Stir and set aside.
Next, prepare the salsa. in a small bowl, place the tomato, red onion, chilli, fresh coriander, a pinch of the spice mix and 2 tbsp. lime juice. Stir to combine. Set aside covered until needed.
Sprinkle the chicken thighs with some of the spice mix.
Place the chicken on the barbecue or in a cast iron pan in the wood fired oven. Cook flipping once for 4-5 minutes or until it cooked through. Remove from the heat and set aside on a board for a minute to let the juices settle.
In the meantime, add the peppers and onions on the barbecue and grill for 2-3 minutes until just softened. remove from the heat into a bowl. Add the fresh garlic, season with some spice mix and extra salt and pepper if needed.
Warm the tortillas over the Bbq or in the wood oven. Slice chicken thighs thinly and serve in warm tortillas with the vegetables, some avocado slices if using, dollop of salsa, drizzle of lime. Enjoy immediately with extra dip such as sour cream, jalapenos, grated cheese or other if desired!