Place the beans in a pan of boiling water, lightly salted and cook for a few minutes. Once cooked drain the beans and allow to cool. Cut the cherry tomatoes in two and place on a plate. Mix together the onion, tuna and cooked green beans in a bowl, then add the olive oil, vinager, salt and pepper. Place a large frying pan over medium heat and melt the butter. Add the Pan-Fried Gnocchi and cook following the instructions on the pack, then set to one side. Mix together all of the ingredients on the plate, cutting the hard boiled eggs into quarters before adding last and serving.