Classic Peruvian ceviche (cebiche or seviche are the proper spellings that nobody uses anymore) consists of 4 ingredients: fish, lime juice, onions and chillies. It is normally served with sweet potato and choclo (Peruvian white corn). Less common accompaniments include potato, yuca (cassava), yuyo (seaweed), rice (!). Cancha is normally served as a snack, although some restaurants serve some as part of the dish. Buen provecho!