• Trim tuna fillet to a long rectangle.
• Finely chop green chillies, combine with green ants, soy sauce and sugar. Cover the tuna with the marinade mixture and set aside.
• Cook crab in a large saucepan of boiling salted water for 8-10 minutes, cool and pick flesh from shell and claws. Set flesh aside and discard shell.
• Crack the coconut, pour the water from the coconut into a small saucepan and place over medium heat to reduce to a syrup consistency. Set aside.
• Scrape flesh from coconut and slice thinly. Place in a bowl with along with finely shaved palm heart and Thai basil, mint, coriander and purple mukunuwenna leaves.
• To make the dressing, combine coconut water reduction with lime juice, yellow palm sugar and salt.
• Mix all salad ingredients and dress with ¾ of the dressing.
• Shave taro into very fine slices. Heat oil in a frying pan, shallow fry taro slices until crisp and golden and drain on absorbent paper.

To serve

• Heat a frying pan and sear marinated tuna on all sides. Let rest.
• Slice tuna and arrange on plate, top with dressed salad and taro crisps, drizzle remaining dressing over dish.