Finely chop the tomatoes, cucumber, spring onions and pepper and place in a bowl.
Separate the yolks from the whites of the hard boiled eggs. Finely chop the whites and add to the vegetables.
In a pestle and mortar, pound the cooked egg yolks with the garlic and a little salt to a paste. Whisk in the vinegar and then the oil until completely amalgamated. Season, then pour over the vegetables.