1, For the tuna tartare, combine tuna, chives, olive oil, lemon zest, salt and pepper in a mixing bowl.
2. For the wasabi avocado, mash the avocado, drizzle over the lemon juice to prevent it discolouring and season with mayonnaise, wasabi and salt.
3, For serving, use 9cm ring mould.
4, Take one spoonful of tuna tartar and spread at the bottom of the ring mould. Flatten the surface. Spread the wasabi avocado on top. Remove the mould and serve with tortilla chips.