Cook potatoes in a saucepan on medium heat for 10 mins or until just tender. Drain, quarter and place into a bowl.
Place capsicum , garlic, tomato paste, paprika and chilli flakes into a small food processor motor running, slowly add 1/4 cup of the oil and process until sauce is almost smooth. Season with salt and pepper. Makes about 1 cup.
Heat remaining oil in a late deep frying pan over medium high heat. Cook chicken in batches for 3 minutes or until browned. Transfer to a bowl.
Add chorizo, onion and potatoes to pan. Cook, stirring often, for 10 minutes or until golden.
Return chicken to pan. Add 1/3 cup water and cover. Cook for 5 minutes or until chicken is cooked through.
Roughly chop half the oregano and stir through chicken mixture. Serve with romesco sauce on the side.