Finely chop the onion, then put it in a small bowl filled with water and a few drops of vinegar. Let stand for about 30 min at room temperature or overnight in the refrigerator. This makes the raw onion crispier and easier to digest.
Pour the olive oil and lemon juice into a salad bowl. Add the spices, salt and pepper. Using a fork, whisk the vinaigrette until it is emulsified.
Drain and rinse the chickpeas, then place them in the salad bowl. Dice the tomatoes discarding the seeds, then put the pieces into the bowl. Finely chop the mint then add it to the salad. Add the previously chopped onion. Toss well to combine. Adjust the seasoning.
Let the salad stand about 10 min to allow the flavours to develop.