Place the lime juice, sesame oil, mirin, ginger, caster sugar and salt in a bowl and stir to combine. Place the tuna in a bowl, pour over half the lime marinade and toss to coat. Cover and refrigerate for 30 minutes. Heat a char-grill pan or barbecue over high heat. Char-grill or barbecue the tuna for 30–60 seconds each side or until just browned. Slice into pieces and thread onto skewers. Stir the coriander through the reserved marinade and serve with the tuna skewers. Serves 4.
+ Mirin is a type of Japanese rice wine with a lower alcohol percentage than other rice wines such as sake. It can be bought in the Asian aisle of your supermarket or at specialty Asian grocery stores.