Separate the egg white from the yolk of the hard-boiled eggs, dice and set aside. Crumbly crush the egg yolks with a fork. Finely chop the garlic cloves. Mix the egg yolks with the garlic, oil, vinegar, water and the spices to make a dressing.
Drain the kidney beans, corn and tuna, crumble them into pieces, in a sieve. Cut the bell pepper and cucumber into cubes. Cut the vegetable onions into rings or cubes as desired and mix everything together in a large bowl with the dressing.
It is best to leave it covered overnight in the refrigerator and put it out the next day 1 hour before eating, then it tastes even better. If necessary, add a little salt and pepper to taste.