Lime buttermilk dressing
1.Blend or process the chopped coriander and the root and stem mixture with chilli, garlic, spices and ¼ cup of the oil until smooth. Combine the coriander mixture and fish in a large bowl. Cover; refrigerate 30 minutes.
2.To make lime buttermilk dressing; combine ingredients in a small jug; season to taste.
3.Heat remaining oil in a large frying pan over medium-high heat; cook fish, in batches, until browned both sides and cooked through. Cover to keep warm.
4.Meanwhile, heat tortillas according to directions on packet.
5.Divide lettuce, cucumber, fish and dressing between tortillas; wrap firmly to enclose filling.