Open Tuesday through Thursday, 11:30 a.m. to 9:30 p.m.; Friday, 11:30 a.m. to 10:30 p.m.; Saturday, 11 a.m. to 13:30 p.m.; Sunday, 11 a.m. to 9:30 p.m. BA, MC. Reservations except Saturday and Sunday lunch.

Food: Daring dim sum and dazzling Cantonese dinners

Style: Serene service amid leftover Polynesian hoopla

Price: Dim sum average ninety cents, main dishes average $4 to $6

WHOEVER is keeping the list of Washington's qualification as a big-time city has to add one more mark because of the Tung Bor restaurant. Dim sum, also known as Chinese pastry, is the reason. Now, dim sum eating has been a growing preoccupation for many years, but nothing like the dim sum scene at Tung Bor has been seen here before. You many have found in San Francisco and New York a Chinese restaurant with rolling carts of stuffed doughs and meaty tibits which you choose by pointing at the fragrant display glides past your nose. But hardly any place else in the country goes to such dim sum lengths, and certainly no place else in Washington. Thus, if Chinatown looks underpopulated these Sunday afternoons, it is because of Tung Bor. Midday Sunday every table is crowded with chinese families, and more wait in line, not to mention the ones who are carrying out boxes of dim sum for teatime at home.

This is the way it works. A pot of tea (jasmine, if you are savvy enough to ask) is set on your table, along with a pink slip that looks like a graph paper. Then you wait for the carts to roll past your table. As you choose, a plate of two to four dim sum is put on your table, and a mark is made on your pink sheet - each mark representing a ninety-cent portion (in the case of two specialties, for $1.25 and $1.50). You pace your own meal, but the tendency for the uninitiated is to order everything that runs past the table, and groan over what they miss once they are stuffed. At the other extreme are the experts who know exactly what they want, and grow hungrily impatient waiting for it, feeling sure that the traffic pattern is sending all the best carts down the aisles. To solve the problems at boths ends, ask for a list of the dim sum to get an idea of what you want, and ask the waitress to roll your favorites by as they come available. The whole process is easier - if less fun - on weekdays, when you order dim sum from the list rather than from carts.

As to what to choose, I'd start by suggesting everything. But with thirty to forty varieties, I recognize that's unrealistic. So, to narrow it down, there are steamed, baked and fried pastries, salty and sweet ones, and you might as well sample a variety. Among steamed ones (you can spot them coming in round metal or bamboo steamers), the pork-filled char shiu bows illustrate how light the breaklike dough can be, how moist and salty-sweet can be the filling. Har gow are a tiny noddle-wrapped contrast, shrimp-filled and crunchy with water chestnuts. Less familiar, even to dim sum aficionados, are the lotus leaf-wrapped bundles of sticky rice with chunks of duck and sausage. If you like the pungency of fresh coriander, the shrimp-stuff fon gor are delicate steamed turnovers worth trying.

Some of the best of the dim sum are baked - lightly glazed char shiu bows - and fried - fragile, crisp spring rolls that the waitress cuts with a scissors as she serves them. There are chewy, faintly sweet fried shrimp dumplings; chicken taro dumplings that are both meaty and starchy with ground shrimp. Only the bean sheet rolls - like stuffed cabbage with bean sheets instead of cabbage - and the undercooked open-topped shiu mai were disappointing.

It is sticking one's neck out to recommend Chinese pastries to American palates, but Tong Bor serves extraordinarily good, fragrant egg custard tarts with flaky crust, and an almond sweet cake that looks and tastes like a cross between sponge cake and clouds. The sweet walnut rice noodles cake must have been the original inspiration for Rice Krispies bars, but almost unrecognizable subtle.

All this totals - when you take your checked-off sheet to the cashier - a numbing feast for less than $5 a person (well, $7.50 if you are a true glutton). Al this served by shyly attentioned waitresses, overseen by a proprietor both suave and gracious. All this set in the leftover splendor of what was a Polynesian restaurant, the papier mache stone walls and wicker thrones softened by sedate Chinese art and silk flowers.

Dim sum is such profusion and quality is enough reason for a detour to Wheaton. But dinner at Tung Bor is no less enticing. Again, tea greets you with the menu, which lists nearly 150 dishes to remind you that Cantonese cooking is varied and stunning in its possibilities as all the newly popular fiery cuisines combined. Duck is prepared ten different ways - with lemon, taro, four treasures or just handsomely roasted, fat-free and juicy. You could order snails or abalone or conch or squid, as well as the more common shrimp, in a dozen fashions. Vegetables come stir-fried or braised, either in cream sauce or oyster sauce. As for beef and pork dishes, they range from beef with ginger and scallions to diced roast pork with cashews. The array bewilders, and some of the waitresses are not fluent in English, so the proprietor gently places suggestions. It is hard to image any of them being amiss, since sampling displayed beautifully theintricate contrasts of colors and textures, the subtle interplay of seasonings that qualify Cantonese among the great cuisines. The sauces were light and limpid, not an overdose of cornstarch or grease among them. Each vegetable held its crunch and freshness.

Don't get carried away with frugality, however, that you miss that taro nest with sea treasures (which is not on the menu, but we found it on the list of specials at the table). A crisp basket of lacy fried taro puree is filled with the stuff of hungry dreams: duck, scallops, shrimp, abalone, pork, squid, broccoli, straw mushrooms, bamboo shoots, and even a ring of deep-fried quail eggs, the whole conglomeration in a garlic-and-ginger-scented sauce. A spectacle to see, it is a classic contrast of crisp and soft, spicy and bland, dark and pale. Another version of Cantonese brilliance is rainbow beef, a julienned stir-fry mixture of bright, crisp carrots and tender rare beef, bright red peppers with white onions and green celery, pungent scallions with faintly sweet pickled radishes, grandly presented on a bed of shredded scallions. A hint of sweet, a tinge of sour, an underlying smoky flavor, it is a pot of gold.

Such food deserves fanfare. And so, dishes are served in sequence, as is their due. They are garnished with fruit and vegetables cut like flowers or positioned to represent butterfly wings. And such food is well worth its prices, most dishes ranging from $4 to $6, with luxuries like duck and lobster, or the taro basket, up to $8.50. While you could easily spend $25 a couple, you could easily be glad you did so. And you could rediscover the deceptively simple pleasures of Cantonese food, even remembered how good an egg roll can be.