Drain the can of mackerel and remove the fish. Clean the mackerel by removing the fins and bones from the top and front. I also remove some of the dark meat, but that’s optional. Open the mackerel and take out any remaining bones. Gently break the mackerel into bite-sized pieces, but don’t shred it completely.

In a bowl, whisk together the olive oil, vinegar, salt, and pepper. Add the vegetables and cilantro, and mix well. Add the mackerel and gently fold it in so it doesn’t break apart too much.

Cut the avocados in half and remove the pits. Use a spoon to scoop out the avocado halves in one piece. Fill the avocado halves with the mackerel salad and serve with a side salad.