Thai Square has renovated recently and now has a clean, spare dining room with a red color palate. Luckily, the kitchen is still the same and they still deliver good, authentic Thai food.
I went there with a Thai friend who ordered for us. Generally, all the dishes were good. The green papaya salad with pickled crab was fantastic. My friend had the foresight to order it less spicy than normal because even toned down, I found it incredibly fiery. Nonetheless, paired with the coolness of shredded papaya and the tartness of the dressing and pickled crab, it was a wonderfully refreshing starter for our meal. If you want to get it with the pickled crab, you have to ask for it specifically. But, I should warn the squeamish: it's raw, so don't get it if you have an aversion to raw shellfish.
The other entrees were nearly as good. My friend ordered a beef hotpot soup with meatballs, shredded beef, and greens, which were liberally seasoned with cilantro. Since I'm a cilantro junkie, I thought it was very good. Another dish we ordered was the crispy pork with Chinese broccoli: generally a solid dish anywhere, but the crispy pork skin that came with it imparted an interesting texture to the dish. Sort of like a side of pork rinds with your greens, which I heartily approve of.
Probably my favorite entree was the softshell crabs with chili-tamarind sauce. The softshell crabs were pan-fried and you have the option to pour the chili sauce over it. What you get is the inimitable crunchy texture of softshell crab and the fiery and subtle sweetness of the chili sauce. My one criticism would be that the sauce is so pungent that it can drown out the flavor of the softshell crab, but the sauce is so good that it makes up for that one shortfall. This entree is a special, and will be taken off the menu once the softshell crab season is over, so get it while you can.
One of the house signature dishes, the crispy honey roasted duck with basil, was quite good. Each small nugget of duck was covered in batter and smother in a sweet, piquant sauce that was not too spicy. My one issue with this dish is that you get a mouthful of batter every time you took a bite and couldn't taste the duck. It was still a good dish, but I wish the duck flavor was a little bit more pronounced.
All in all, a very good Thai meal. As my friend told me, this is probably the best (and only place) to get authentic Thai in NoVa. Just be forewarned: it gets extremely crowded on weekends and there is limited parking.