Place olive oil in a large frying or wok and cook the onion, garlic and red pepper for five minutes. Add in the turkey mince and break up the meat, cooking until it is no longer pink. Add the chilli powder, cumin, oregano, cayenne pepper and stir through. Now add tomatoes, chicken stock, kidney beans and sweetcorn. Bring to the boil and then reduce the heat to simmer for 30 to 45 minutes. Just before serving add the kale or spinach to the pan and cook until soft.