Octopus has been popping up as a appetizer on menus at all kinds of restaurants, from Italian to New American. But if you want to taste it at its best, go to the Greeks, specifically Periyali, Chelsea's refined Greek restaurant. Here the octopus, marinated in red wine and grilled over charcoal, is meaty yet tender. The flesh is firmer and gutsier than that of any fish. The plate is adorned with nothing but a lemon, and that's all it needs. It's a refreshing change from other, chewier versions we've had. And this is one restaurant where the first course does not outshine what follows. You'd be hard pressed to find a better moussaka-layers of eggplant, spiced ground lamb, and bechamel sauce. It's the Greek equivalent of shepherd's pie, but this version is surprisingly light. Also outstanding are the veal medallions served with a mushroom sauce and spinach. You won't find any surprises on Periyali's menu, but you will find classic Greek food done right, with atmosphere and service to match. Some say it's the best Greek restaurant in the city, and they may well be right.Periyali35 W. 20th Street between 5th and 6th Avenues Tel: 212-463-7890