Drain the canned tuna. If you have fresh tuna, fry it briefly in the pan with a little oil on both sides (approx. 2 - 3 minutes per side), season with salt and pepper as required.
Finely chop the onion and tomato. Mix both with a little lemon juice, olive oil and the finely plucked tuna, season with salt and pepper (it can be prepared in this way and stored in the refrigerator in the closed container).
Halve the avocados, remove the pit and drizzle with lemon juice to prevent them from browning. Now you can either fill the halves with the tuna salsa or take the avocado out of the shell, cut into strips and fan out and serve with the salsa on the plate. Garnish everything with coarsely chopped parsley or other herbs.
Tip: if you like, you can add some artichoke quarters.
Ideal as a light summer meal or as a healthy starter.