Drain the chickpeas, rinse briefly, drain and transfer to a large bowl. Wash and clean celery, spring onions and tomatoes and cut into small pieces. Wash and chop the parsley too. Put everything in the bowl.
Wash the lemon, dry it well and rub about 1/2 teaspoon of the zest. Squeeze half of the lemon. Put the juice and the peel into the bowl along with the olive oil. Season to taste with salt, pepper and the ground cumin. If you like it a little hotter, you can also add chilli flakes. Mix everything well. Only cut the avocados into pieces at the end and mix in as well, as they tend to melt if they stir too much due to their soft consistency.
Let it steep for 30 minutes and season if necessary.