Heat the olive oil in deep saucepan and fry the chorizo sausage for 2 minutes to release its juices in the pan. Add in the garlic and onion and cook for a further 5 minutes. At this point, the onion should take on and golden orange colour. Add the carrots and celery and cook, followed by the smoked paprika and dried chilli flakes. Stir the ingredients together well and continue to cook for another 5 minutes to soften the vegetables. Pour in the chicken stock, along with the lentils and chickpeas. Season the soup well with salt and pepper, cover with a lid and reduce the heat. Continue to cook the soup for another 20-25 minutes, or until the lentils are cooked through. Just before serving, stir in the chopped parsley and serve the soup in deep bowls.