First, drain the tuna then transfer it to a bowl. Add the chopped cilantro in the tuna and mix well with a teaspoon of mayonnaise.
Prepare another bowl for the sliced hard-boiled egg. Stir with another teaspoon of mayonnaise.
Place the avocado, pepper, and tomato on a cutting board. Chop into small squares.
Use a ring mold to layer the salad. Place the avocado on the base, next is the pepper, the tomato, then the egg mix, and finally the tuna mix right on top.