Ahi Tuna Ceviche with mango and avocado from The Hog Island Book of Fish & Seafood: Culinary Treasur

Ingredients

• 1 teaspoon minced fresh oregano
• 1 teaspoon seeded and minced serrano chile
• 1 tablespoon olive oil
• 2 tablespoons coarsely chopped fresh cilantro
• 1¼ pounds (570 g) sushi-grade ahi tuna, cut into ⅓-inch (8-mm) dice
• Fine sea salt and freshly ground pepper
• Tortilla chips, for serving
• ½ cup (120 ml) fresh lime juice
• ½ cup (85 g) seeded and diced ripe plum tomatoes
• ¼ cup (15 g) green onion, cut into thin diagonal slices, including green parts
• 1 large avocado, pitted, peeled, and cut into ⅓-inch (8-mm) dice
• 1 mango, peeled, pitted, and cut into ⅓-inch (8-mm) dice
• Fresh cilantro sprigs, for garnish