2 1/2 tablespoons cumin seeds
3 jalapeño chilies, stemmed and cut in half
2 cloves garlic
2 1/2 teaspoons salt
1 tablespoon plus 1/2 teaspoon freshly ground black pepper
1/4 cup plus 3 tablespoons freshly squeezed lime juice, divided
1 large bunch plus 6 tablespoons chopped fresh cilantro, divided
5 ripe avocados, preferably California Hass
1 medium red onion, diced
4 jalapeño chilies, stemmed, seeded and finely diced
1 cup salsa
1. Make marinade: Lightly toast cumin seeds in a dry skillet over low heat just until aroma is released, about 5 minutes. Transfer seeds to a blender. Add 3 jalapeños, garlic, 1 teaspoon salt, 1 tablespoon pepper and 1/4 cup lime juice and puree until cumin seeds are finely ground. Add 1 bunch cilantro and olive oil and puree until smooth.
2. Using hands, generously cover Alaska Cod entirely with marinade and let sit at room temperature for 20 minutes.
3. Preheat a medium-hot grill, broiler oven or pan on the stovetop over medium-high heat.
4. Cook fish until nearly opaque throughout, about 2 to 5 minutes per side, depending on thickness. Remove fish from heat, cool slightly, and pull apart into large flakes.
5. Make guacamole: Cut the avocados in half. Remove the pits, peel, quarter and place in a mixing bowl. Mash with a potato masher or fork until chunky. Add 6 tablespoons cilantro, red onion, 4 diced jalepenos, 3 tablespoons lime juice, 1 1/2 teaspoons salt and 1/2 teaspoon black pepper; combine with a fork. Serve immediately.
6. Assemble tacos: Place warm tortillas on a work surface and line each with a piece of lettuce. Top with chunks of fish, a generous spoonful of salsa fresca and guacamole. Serve immediately accompanied by lime wedges.