The white grouper aguachile with coriander pesto and spicy salsa at Omega3. | Nat Belkov It felt like everyone I know traveled to Greece this summer. Friends chose Zakynthos, Crete, Naxos, Ikaria. I opted for Sifnos, one of the Cyclades’ most celebrated food destinations but still, thankfully, relatively under the radar internationally. Greece’s culinary culture can’t be grasped fully on any one island; across the Aegean, distinct growing conditions and cooking traditions have produced individual cuisines entirely their own. Sifnos just happens to have a particularly delicious…