926-A W. Broad St. Falls Church 534-0095 (-96) Hours: 11 a.m. to 10 p.m. Sunday through Thursday; 11 a.m. to 11 p.m. Friday and Saturday. Prices: Appetizers and soups, $1.50 to $5.50; salads and entrees, $1.95 to $12.95 (most under $6). Cards: MasterCard, Visa. No nonsmoking section.

At the two-month-old Bangkok-Vientiane, the menu is a combination of Thai and Laotian. It's a logical fusion not only because the chef, Manit Kulsrisombart, is Thai and his wife, Khoune, the restaurant manager, is Laotian but also because the cuisines have much in common. Both, for example, use such seasonings as basil, hot peppers, coconut milk, curries, fish sauce, tamarind and lemon grass.

Although there are some differences between the two cuisines, they tend to be subtle -- at least as executed here. According to Khoune Kulsrisombart, the Thais like their food sweeter and more sour, and use seafood more frequently than the landlocked Laotians. While Thais serve steamed rice with their meals and eat with forks and spoons (chopsticks are reserved for noodle dishes), Laotians serve sticky (glutinous) rice and often eat with their fingers (except they, too, use chopsticks for noodle dishes).

Sticky rice is not only an accompaniment for the Laotian entrees, but also a staple, like bread on American and European tables. Clumps of the sticky rice typically are dipped into one of many varieties of jieo, a spicy, garlicky sauce that is served on request.

There are fewer than 50 seats in this former pizza parlor. (The pizza ovens are still in place, but are now used to warm plates, sticky rice and the restaurant.) The decor is simple and bright with light wood, red vinyl seats, red checked tablecloths, and gold and white lattice-patterned wallpaper that suggests bamboo.

The modestly priced menu features a half-dozen Laotian specialties, but generally a dish is either Thai or Laotian depending on whether it's ordered with steamed or sticky rice.

For starters, the fried spring rolls, advertised as Laotian, are tasty but slightly greasy and, not unlike Thai versions, stuffed with a dense blending of sausage, crab meat and transparent noodles. The soft, uncooked spring rolls, also similar to other Southeast Asian renditions, are filled with thin rice noodles rolled with fresh coriander leaves, and a slice of beef and shrimp. These translucent packages of white, pink and green look pretty but always remind me of eating low-calorie rice cakes when I'd rather have croissants.

Among soups there are several terrific choices, including the spicy lemon grass varieties, tom yum goong with shrimp, and -- on occasion -- po tak, billed as a Thai bouillabaisse. Also good is mildly spicy chicken with coconut milk and galanga (ginger). For the adventurous, try the delicious fish maw soup in a chicken broth base with quail eggs, fresh coriander, pieces of chicken, bamboo shoots, mushrooms and spongy pillows of reconstituted fish maw (fish intestine).

The highlight of the "Lao popular salad" ($5.25) is the marinated beef cut into thin strips, dried and fried to a crisp, dark brown. The nicely chewy strips surround a mound of shredded green papaya tossed with bits of tomato and baby shrimp in a sweet vinegar dressing. With sticky rice, this makes a satisfying meal. The meat also can be ordered alone as an appetizer for $4.95.

The Lao pasta was a big hit with a wonderful, soupy curry sauce and rosy slices of beef. It is also available with chicken, pork or shrimp. The pud Thai noodles, though, were disappointing because some salted baby shrimp gave the dish a faintly fishy taste.

On the other hand, two fried fish fillets are standouts -- one topped with a tamarind sauce that is a heady mingling of fragrant herbs, hot peppers and sweet and sour flavors. Almost as good is another fillet that is bathed in a rich, pungent chili sauce.

The lab Lao, a cold, diced beef salad with thinly shaved pieces of tripe, is not for the faint of heart. It is so incendiary that one dining companion doubted that all the sticky rice in Laos could tame its fire. I enjoyed it with a 3-to-1 ratio of rice to beef (or, if one prefers, the kitchen will prepare a milder version).

A flavorful grilled chicken special was successful and not at all spicy, although its chili pepper sauce needed some zip.

Agreeable but not distinctive was the roast red pork, tender slices in a slightly sweet brown sauce.

Stir-fried vegetables, such as the tasty watercress, benefit from a salty black bean mixture.

One of the Laotian desserts intriguingly named "singapo and ruby in syrup" is a sweet coconut milk "soup" with an assortment of red, white and green bits made from water chestnuts, tapioca and rice flour. It's a light finish and fun to eat. Ditto for the special pink voun, which is also coconut milk-based with unflavored gelatin and sweet, transparent canned palm seeds.

An acquired taste among the desserts is the flavor of sauteed shallots atop sweet caramelly Thai custard. A more familiar choice is the coconut caramel.

The small staff is helpful and attentive, but can be pressed when the room is even half full. Nonetheless, any lag in service is worth the wait.