Mix the garlic, oil, vinegar, mayonnaise and mustard in a bowl. Season with salt and pepper and set aside the dressing.
In the meantime, arrange the rocket on a plate.
Boil the beans in a saucepan for about 8 minutes, then rinse in ice water. Fry the meat in the butter and keep warm. Peel the potatoes and cut into slices.
Mix the potatoes, chicken, beans and tomatoes, add to the rocket salad and sprinkle with capers. Spread the dressing on the salad.