Preheat the grill to high. Heat a 20-21cm non-stick, lidded, ovenproof frying pan over a medium-high heat and add the chorizo. Fry for 5 minutes, until crisp, stirring frequently. Remove the chorizo with a slotted spoon and place in a large bowl.
Add the onion and green pepper to the pan and cook for 5 minutes, until starting to soften. Add the olive oil and sweet potatoes to the pan. Cook for 2 minutes, then reduce the heat to low and cover the pan with a tight-fitting lid. Cook for a further 15 minutes.
Meanwhile, add the eggs, paprika and cheddar to the bowl with the chorizo. Season to taste and whisk together.
Once the vegetables have softened, remove them from the pan with a slotted spoon and add them to the bowl with the eggs. Mix to combine. Drain off all but 1 tbsp of oil from the pan.
Add the potato mixture back to the pan and place on a medium heat. Cook for 2-3 minutes until the bottom has set and is golden. Place the pan under the grill and cook for a further 3-5 minutes, until the top is nice and golden and the tortilla is set. Serve warm or cold cut into wedges with the salad.