Place the slices of tuna on a plate. Garnish with the red onions. Squeeze lime juice all over and top with the avocado and jalapeno. Drizzle with the soy sauce. Serve immediately with crackers.
Warning: Consumption of raw or undercooked shellfish may substantially increase the risk of foodborne illness.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.