Chop the tuna fairly finely but do not puree it; stir in the garlic, soy sauce and coriander and mix well; form into 4 burgers and press down until about 1.5cm thick
Mix the seeds on a plate then press the burgers into them until well coated all over; chill for 20 minutes
To make the salsa, peel and finely dice the mango; mix with the chillies, spring onions and coriander and then squeeze over the lime juice; toss together and season to taste
Toast the burger buns, heat the oil in a non-stick frying pan on a medium heat and cook the burgers for 2 ½ to 3 minutes on each side, depending on how well done you like them; divide the cabbage between the buns, add the burgers and top with salsa and serve
4 servings