In 1948, an ethnic Greek restaurateur opened a restaurant on an island near Istanbul. When, in the ’60s, people of Greek heritage were forced to leave Turkey, he moved to his ancestral homeland, and reopened the restaurant in Athens. Since 1969 that restaurant, Fatsio, has been serving politiki kouzina, “city cooking,” the food prepared by ethnic Greeks who lived in Istanbul. Today, Fatsio’s beautifully hand-painted walls and heavy velvet curtains retain the old Constantinople vibe. Its custom logo tableware and bowtied, meticulous, and helpful if slightly stiff staff also reflect…