Grilled-Fish Tacos with Roasted-Chile-and-Avocado Salsa

INGREDIENTS

• 2 poblano peppers
• 1 jalapeno chile
• 1/2 Hass avocado, peeled and pitted
• 1/4 cup plus 3 tablespoons olive oil
• 3/4 cup chopped onion
• 3/4 cup cilantro leaves
• Juice of 1 lime
• 1 1/4 teaspoons coarse salt
• 1 halibut fillet (1 pound)
• 1/2 teaspoon freshly ground white pepper
• 8 fresh white or yellow corn tortillas, warmed according to package directions
• 4 slices ripe tomato, cut in half
• 2 limes, halved, for serving