Mekong River: A tasty alliance of sophisticated Asian cuisines.(Vietnamese restaurant)

Naming a Vietnamese restaurant after the Mekong River, the 2,600-mile-long waterway that flows through six countries on the Indochina peninsula, is as localizing and evocative as calling a Cajun place the Atchafalaya River Cafe.

That's why Kevin Tran and his chef wife, Pirin Kunviboon, promptly rechristened the Dalat Vietnamese Bistro when they took the restaurant over from Janet Nguyen in March.

The new proprietors of this attractive split-level Summit Square eatery changed more than the sign over the door, however. They doubled the size of the menu, augmenting it with dishes from Kunviboon's native Thailand.

Combining two of Asia's most sophisticated and delectable cuisines, this culinary alliance forces diners to choose between mild and hot. There are no warning asterisks or drawings of chili …