Make sure you pat the tuna fillet dry using a paper towel.
Use a sharp knife to dice the tuna into 1 inch dices.
Try to keep the size uniform as much as possible and avoid making too small of chunk, as this will cure quickly in the marinade.
Now mix all the marinade ingredients in a bowl.
Add in the tuna and mix well.
Repeat with the avocado mixture, mix everything together in a separate bowl.
Now to assemble the tartare, take a mold or ramekin or bowl.
Oil the indies of the bowl or mold using a brush.
Start by placing the avocado at the bottom layer (if flipping a bowl then start by the tuna layer) and press it down.
Now add in the tuna layer and press it down.
Carefully remove the mold and you'll have tuna tartare stack.
Serve with some pita chips or cucumber rounds.
