Open Tuesday through Thursday 10 a.m. to 10 p.m., Friday and Saturday 10 a.m. to 1 a.m., Sunday 8 a.m. to 10 p.m. Closed Monday. MC, V. No reservations. Prices: Sandwiches $3.65 to $7.50; appetizers and soups average $2 to $3, hot platters average $5.25 to $8.75.

You don't just open a deli; you raise one. So don't go

expecting Zeltner's, three months after its opening, to

be the fullblown New York deli of your dreams. A little

patience, please.

The signs are good.

Zeltner's is bringing well-pickled corned beef to Washington, and smoked sable fish that, as the saying goes, could melt in your mouth. Zeltner's kitchen knows how to whip up an airy matzo ball, and chops liver like nobody's business--with sweetly fresh chicken livers, chopped eggs and, as our deli dreams would have it, the cracklings from rendered chicken fat.

But Washington is so mythically unfamiliar with authentic delis, that it is time to back up for an introduction. Zeltner's as a deli: You enter smack into the deli case. Four kinds of sliced- to-order smoked salmon (all at take-your-breath-away prices, but try the Norwegian; it's the most delicate as well as the prettiest). Reasonably homey looking corned and fresh briskets, roast beef, fish salads, more than a half-dozen cream cheese combos, maybe a basket of cookies perched on the counter reminding you of your sweet tooth. And a line.

Delis are wonderful-smelling places that have turned irritation into an art form. This one requires sit-down patrons and carryout patrons to pay at a single cash register, making it not only the neighborhood social center but also the whining department.

The dining room is small and plain, its main decoration being a pair of Victorian portraits. That's okay--a deli isn't supposed to look like the French Riviera. But the tables are so small that you hesitate ordering anything more than half a sandwich.

Which brings us back to the assets: Zeltner's is flexible. It lets you order half a sandwich. Or an extra-large sandwich. Or half a fish platter. Or taste a sample of whitefish salad or cheesecake before you decide. You want it, they got it, you can have it. None of this "I'm sure the kitchen won't allow it" business.

Zeltner's is at its best for Sunday brunch. At its best, in a deli, means that it is a madhouse; not only are people lined up for tables, but they are table-hopping and passing samples back and forth, reading the paper and maybe dozing when you're waiting for their table. A man in a tuxedo eating a hot dog and a pickle on Sunday morning--that's Zeltner's.

What else you eat for Sunday brunch is smoked fish: one of those four kinds of smoked salmon, moist and smoky whitefish either sliced or in a salad, that impeccable sable, sturgeon if you have such elevated tastes. With those you get chewy, crusty bagels from Georgetown (Washington's new Lower East Side) and a choice of cream cheese (though if you choose anything but plain or chive, you'll never make it in Manhattan). You order Zeltner's Deli Hash, big chunks of that tangy corned beef sauteed with a little potato so that it tastes like all the crusty ends you love to nibble. Or you try lox, eggs and onions, even if you've had it elsewhere and didn't like it, because here they know enough to leave the eggs creamy and the lox just warmed, not cooked into salty toughness.

Any time of day you order latkes, thick and lacy-crusted potato pancakes that could make french fries taste boring, even though Zeltner's are too greasy and too salty. They come with Zeltner's own applesauce, tasting of real apples and inundated with cinnamon.

This is, and rightly so, a restaurant of strong tastes. And dense, heavy textures. And greasy intensity. The mushroom-barley soup is, by all standards, too thick and starchy in texture. But even so, such an earthy soup is a pleasure to encounter. The borscht, no lipstick-pink clear beet broth, is hot and thick with cabbage, larded with chunks of meat, a real homemade soup (though next time I hope they go easier on the water in its proportioning). Zeltner's serves you a bowl of pickles as soon as you are seated, and now it has even found some sour dills to add to the half-sours. You order a seltzer (literally 2-cents plain) or a milky chocolate soda called an egg cream. As of my last visit Zeltner's had no liquor license, but there may be one on the way.

Most of the menu, which is mimeographed daily, is sandwiches. Big fat ones on rye bread that isn't the best on the East Coast, but has been exposed to air rather than the inside of a plastic bag, so the crust still bites back. And it hasn't been sliced until right before you get it. The daily specials are mostly pot roasted and boiled meats such as chicken or flanken in the pot, a kind of meal-in-a-soup with noodles, matzo balls, carrots, celery and parsnips. By now the servers should have been sufficiently reminded to bring the horseradish. On the side you can get kasha, kishka, cabbage salads (bland and unappetizing every time we tried them), or other salads. Try the potato; as long as it has been freshly made, it is marvelous potato salad with just enough onion and not too much mayonnaise. You can get knishes, too, but they are the bright yellow, doughy type you have to have learned to love on the streets of New York, I suppose.

Zeltner's serves a couple of homemade cakes--the cheesecake is better than most of your mothers used to make--and sometimes there are wonderfully gooey brownies. Otherwise the desserts are primarily the same Country Epicure cakes being sold everywhere around town. The cheesecake and a thick white mug of good coffee help ensure this deli's future.

A lot needs to get done along the way, though. The hostesses are the eagle-eyed, gregarious, maternal sorts that are one good reason for our having wanted a deli. But the waiters and waitresses have had a lot to learn-about forgetfulness, about spilling and dropping things, about seeing that a table has everything it needs, about checking with patrons from time to time. Progress has already been made, and a couple of waiters have been especially quick to learn. The roast beef started out bland and watery, and it, too, has come along. The greasiness of the latkes, the too-thin and over-steamed pastrami, the tasteless health salad and coleslaw, well, we're willing to give them time.

The prices, however, have already turned away many potential fans. Those with such cravings are willing to pay $5 to $6.50 for a proper corned beef sandwich, or $5.45 for lox and eggs. But that doesn't mean that a tuna sandwich is worth $3.80 (more than the Madison Hotel's) just because it is served under the same roof. The same goes for egg salad, salami, sodas. Charging premium prices for such standard foods can be warranted only but luxurious environment and service, hardly the case at Zeltner's. Not all the prices are high, and for matzo ball soup, fine chopped liver and a real corned beef hash, maybe no price is too high. But going in one Sunday for an $8 fish platter, then returning a few weeks later to find it $13.75 (though, admittedly, few other prices were raised) makes one examine everything with a jaundiced eye. Zeltner's needs to distinguish between the rare and the ordinary in its pricing.

But if it keeps going in the same direction, some day Washington is going to have that deli everybody keeps talking about. And it will be Zeltner's.