2. Boil chicken eggs for 8-10 minutes. Peel and cut into quarters.
3. Dressing: mix finely chopped onion, wine vinegar, olive oil, finely chopped basil, thyme, oregano, salt and ground black pepper, grain mustard and Dijon in a jar. Close the jar with a lid and shake well so that all the ingredients are mixed.
4. Cut the red onion into thin rings and marinate in a small amount of dressing.
5. Peel the potatoes and boil until tender (from 10 to 20 minutes, depending on the size of the potato tubers). Cut the boiled potatoes into cubes measuring 1 inch (2.5 cm).
6. Marinate potato cubes in the dressing (about 1-2 tablespoons)
7. Boil string beans in boiling water for 5-7 minutes.
8. Cut tomatoes into cubes the size of potatoes.
9. Assemble the salad: put lettuce leaves on a large plate (pre-rinse them with water and dry), put tuna in the middle, put tomato cubes, pickled red onion, string beans, olives, potatoes, eggs, capers on the sides. Carefully put a few spoonfuls of marinade out of the jar.