Vinh Map
As you'd expect from a seaside town, Ha Tien has excellent seafood restaurants, most of which line the river. Vinh Map is a good place to tuck into fresh shrimp, squid, clams, sea snails, and oysters, which are usually sold by the kilo or half kilo. An English menu helps, but not as much as a bit of confidence and the ability to point at what you'd like to eat.