1 pound raw shrimp (21-25 per pound), peeled and deveined
Juice of 2 lemons
Juice of 2 limes
Juice of 2 oranges
1 cup diced seeded peeled cucumber ( ¼-inch dice)
½ cup finely chopped red onion
2 serrano chiles, seeded and finely chopped
1 cup diced seeded tomato
1 avocado, chopped into ½-inch pieces
1 tablespoon roughly chopped cilantro leaves, plus more leaves for garnish
¼ cup extra-virgin olive oil
¼ teaspoon kosher salt
Combine water and ¼ 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 ½-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 ¼ teaspoon salt into the shrimp mixture. Let stand at room temperature for 30 minutes before serving. Garnish with cilantro leaves, if desired.
Make Ahead Tip: Prepare through Step 2 and refrigerate for up to 4 hours.
Kitchen Tip: A nonreactive bowl or pan—stainless-steel, enamel-coated or glass—is necessary when cooking with acidic foods, such as lemon, to prevent the food from reacting with the pan. Reactive pans, such as aluminum and cast-iron, can impart an off color and/or off flavor.