Set the oven to 180°C/350°F. In a large bowl, mix the garlic powder, paprika, ground coriander, salt, and pepper. Stir in the olive oil and lime juice until it turns into a thick paste. Add the chicken thighs and rub the paste all over them.
For deeper flavour, cover the bowl and refrigerate the chicken for 1 hour, or up to overnight. Short on time? Go straight to the next step.
Warm a large, deep, oven safe skillet with a lid over medium high heat. Lay the thighs in with the skin facing down and cook for about 4 minutes, until golden. Turn them over and cook the other side for 1½ minutes. The centre will still be pink, which is fine, since it finishes in the oven. Move the chicken to a plate.
Take out any blackened spice bits from the skillet, but keep the brown ones. Add the onion and garlic and cook for about 3 minutes, until soft.
Stir in the rice for about 1 minute, until coated in the pan juices. Pour in the stock and passata, add the corn and black beans, and season with salt and pepper. Stir well.
Place the thighs on top of the rice with the skin facing up. Press them in gently so the meat sits in the liquid and the skin stays above it.
Let the liquid come to a gentle simmer, then cover with the lid or foil and bake for 25 minutes. Remove the lid and bake for 15 more minutes, until the rice has absorbed most of the liquid and only a few small pools are left.
Let the skillet stand, uncovered, for 10 minutes so the rice soaks up the last of the liquid. Squeeze the lime over the top, push the chicken aside, and fluff the rice with a fork. Finish with cilantro, avocado, extra lime wedges, and jalapeños if you like.