To make salsa, set aside half the coriander bunch for serving. Finely chop the remaining coriander (leaves and stems) and place into a medium bowl. Add tomatoes, onion, jalapeno and lime juice. Mix to combine.
Place yoghurt in a small bowl. Stir in about 1 tablespoon water to give a pouring consistency. Refrigerate salsa and yoghurt while preparing tortillas and fish.
Place fish fillets in a large shallow dish. Add combined oil, chilli powder, paprika and cumin. Rub spice mixture over fish to coat evenly.
Heat a large, lightly greased, non-stick frying pan over a medium-high heat. Lightly toast tortillas in hot pan for 20-30 seconds on each side, until warm and lightly browned. Remove. Wrap in foil to keep warm.
Cook fish fillets in same non-stick frying pan over a medium-high heat for about 3 minutes on each side, or until fish is cooked and lightly charred. Transfer to a plate. Using 2 forks, break into large flakes.
To serve, top warm tortillas with lettuce, fish, salsa and avocado. Sprinkle with feta and drizzle with yoghurt. Garnish with reserved coriander sprigs. Fold in half. Serve with lime wedges.

Any firm, skinless, boneless fish is suitable for this recipe eg ling, dory, snapper. If preferred, heat tortillas and cook fish on a barbecue flat plate instead of in frying pan. Pickled jalapenos are available from the Mexican food section in supermarkets. Substitute 2 thinly sliced, small, fresh green chillies, if preferred.