Roughly grate the onion, then mix with the egg and mince. Season. Use your hands to make into 6 thick burgers and rub them with oil. Cook on a hot griddle pan or under the grill for 3-5 minutes until browned. Add the chorizo slices to the pan for the last minute of cooking.
Toast the buns. Place the burgers on the buns and top with the chorizo, roasted peppers and leaves. Mix the mayonnaise and paprika, spread on the bread, then sandwich together. Serve with chips and grilled tomatoes.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.