2 medium poblano or hatch chilis
½ pound medium shrimp, peeled, deveined, tails removed
1 small tomato, seeded, finely chopped (about 3/4 cup)
1–2 jalapeños, stems, ribs, and seeds removed, finely chopped
½ cup tomato–clam cocktail, such as Clamato juice
¼ cup plus 2 tablespoons ketchup
3 tablespoons chopped pitted green olives
2 tablespoons chopped fresh cilantro
2 tablespoons finely chopped white onion
1 ½ teaspoons finely chopped oregano
½ teaspoon finely chopped garlic
3 tablespoons fresh lime juice
3 tablespoons olive oil
½ pound crabmeat, picked
1 avocado, pitted, cubed
Tortilla chips or Saltines (for serving)
Prepare a grill for medium-high heat or preheat broiler. If broiling, place chiles on a rimmed baking sheet. Grill, broil, or roast chiles directly over flame on stovetop, turning occasionally, until very tender and blackened all over, 10–12 minutes. Transfer chiles to a large bowl. Cover with plastic wrap and let steam 15 minutes. Peel chiles. Halve lengthwise, discard seeds, and chop into ¼" pieces.
Meanwhile, bring a medium pot of generously salted water to a boil. Cook shrimp until just opaque and pink, 2–3 minutes. Using a slotted spoon, transfer to an ice bath and let sit until cool, about 3 minutes. Drain and pat dry.
Mix chiles, tomato, jalapeños, Clamato juice, ketchup, olives, cilantro, onion, oregano, garlic, lime juice, oil, and 1/4 tsp. salt in a large bowl. Carefully fold in shrimp, crab, and avocado.
Transfer to a serving bowl or tall sundae glass. Garnish with cilantro. Serve with tortilla chips or crackers.