Shrimp Ceviche

1 pound cooked and peeled shrimp, but into 1/2 inch pieces or smaller
1 1/2 cup fresh lime juice
1 medium white onion, chopped into 1/4-inch pieces
1 pound ripe tomatoes, chopped into 1/4-inch pieces
1-2 jalapenos or 2-3 serranos, stemmed, seeded and finely chopped
1/3 cup chopped cilantro
1/3 cup chopped pitted green manzanillo olives
1 tablespoon olive oil (optional)
Salt
1/2 tsp sugar
1 large or 2 small ripe avocados, peeled pitted and diced
Tostadas or tortilla chips

Put chopped shrimp into a bowl with the lime juice and marinate for about 4 hours. Then drain off the lime juice. (You can make this with fish and cook it in the lime juice).

In a large bowl, mix together the tomatoes, green chiles, cilantro, olives and optional olive oil. Stir in the shrimp, then taste and season with salt, usually about 2/4 teaspoon, and the sugar. Cover and refrigerate if not serving immediately.

Serve with tostadas and tortilla chips.