Shrimp Ceviche

Combine water and 1/4 cup salt in a large saucepan; bring to a boil over high heat. Add shrimp and immediately turn off the heat. Let the shrimp sit until just cooked through, about 3 minutes. Transfer to a cutting board until cool enough to handle, about 10 minutes.

Chop the shrimp into 1/2-inch pieces and place in a medium nonreactive bowl (see Tip). Add lemon, lime and orange juice. Stir in cucumber, onion and chiles. Refrigerate for 1 hour.

Stir tomato, avocado, chopped cilantro, oil and 1/4 teaspoon salt into the shrimp mixture. Let stand at room temperature for 30 minutes before serving. Garnish with cilantro leaves, if desired.