1.Preheat oven to 220°C (200°C fan-forced). Line an oven tray with baking paper.
2.In a small bowl, combine cheese and chilli. Drop level tablespoons of the cheese mixture on lined tray, flattening slightly with the back of a spoon. Bake, uncovered, for about 5 minutes, or until browned lightly. Stand until crisps set.
3.Meanwhile, to make chilli lime dressing: place ingredients in a screw-top jar; shake well.
4.Cut tuna into 5mm pieces. Place in a medium bowl with half the dressing; toss gently to combine.
5.Meanwhile, to make avocado salsa: In a medium bowl, place avocado, tomato, onion and coriander with remaining dressing; toss gently to combine.
6.Press a quarter of the undrained tuna into a 9cm egg ring set on a serving plate; remove egg ring, top tuna with a quarter of the salsa. Repeat with remaining tuna and salsa; serve with crisps.
Tuna sold as sashimi has to meet stringent guidelines regarding its handling and treatment after leaving the water. Regardless, it is still probably a good idea to know your fishmonger quite well, or to seek advice from local authorities before eating any raw seafood.