Cook potato in simmering salted water until tender, 10-15 min. Drain; cool slightly. Cut the potatoes into quarters. In a boiling water blanch the beans, for 3-4 min. Drain; run in a cold water. In a big bowl add warm potato quarters, beans, halved tomatoes, eggs and kalamata olives. In a small bowl combine olive oil, vinegar, salt and black pepper. Toss with the salad. Sprinkle with a chopped basil. Serve immediately.