Drain the chickpeas in a colander, rinse with cold water and drain well. Drain the tuna and shred coarsely with a fork. Drain and quarter the artichoke hearts. Clean the tomatoes and cucumber and cut into small pieces. Drain the olives and cut in half, quarter the sun-dried tomatoes. Finally, peel the onion and chop it very finely or chop it finely in a lightning chopper. Mix everything in a salad bowl.
For the dressing, peel the garlic, chop it very finely or press it through a garlic press. Pluck the rosemary needles from the branch and finely chop with the parsley. Mix both with vinegar, oil, salt, pepper and cane sugar or honey to make a homogeneous dressing. This works best in a shaker. Pour the dressing over the salad and mix well.
Let the salad steep for at least 1 hour or overnight.
Shortly before serving, tear up the romaine lettuce or lettuce, fold into the lettuce and season to taste again.