1 - 2 lbs. tilapia fillets, finely diced
1 c. lime juice (about 8 large limes)
1/2 c. tomato, seeded and chopped
1/2 cucumber, peeled, seeded and finely diced
1/2 c. onion, finely chopped
1/4 c. fresh cilantro, chopped
salt and freshly ground black pepper
1/2 c. clam-tomato juice, such as Clamato® (optional)
1 Tbsp. bottled hot sauce (optional)
1 serrano chile (optional)
grilled tostadas (put tortillas on a grill or grill pan and let them dry out until they are crunchy) or purchased tostadas
mayonnaise, for spreading
1 avocado, halved, pitted, peeled and thinly sliced
1 lime, cut into wedges