Peel and finely chop the onion. Heat 1 tbsp olive oil in a large pan over a low heat. Add the onion. Gently cook for 5 mins till the onion is glossy and soft. Stir every so often.
Peel the skin from the chorizo sausage. Slice into rounds. Finely chop or crush the garlic. Rinse the chilli. Halve it and scrape out the seeds and white bits. Finely chop. Add the chorizo, garlic and chilli to the onion. Cook and stir for 2-3 mins.
Peel and dice the sweet potato. Add to the pan with 1 tsp of the cumin and 1 tsp of the smoked paprika. Stir in and cook for 2 mins till the pan smells aromatic and spicy. Fill the kettle and boil it.
Drain the beans and rinse them. Add them to the pan with 2 tbsp of the tomato purée. Stir in 400ml hot water from the kettle. Bring to a gentle simmer. Cover and cook for 15 mins till the potato is tender.
Tip the rice into a small pan. Pour in 250ml hot water from the kettle. Cover. Bring to the boil. Turn the heat right down. Simmer for 6 mins till all the water has been absorbed. Take off the heat. Steam, lid on, for 2-4 mins till the rice is cooked.
Grate or pare the zest from the lime. Rinse and pat dry the parsley. Roughly chop the leaves and stalks. Fluff the rice and stir in the zest and half the parsley. Halve the lime and squeeze one half into the chilli. Taste and season with salt and pepper if needed.
Serve the rice with the chilli, sprinkled with the remaining parsley and a wedge of lime for squeezing.