I recently discovered some great (frozen) leek and pork dumplings at the Asian Market, made by Master Wu. We bought a few packages, and have been in dumpling heaven since. I make my own “sauce” with soy sauce, white vinegar, and a little dot of chili sauce.
They are almost as good as the dumplings at the dim sum place we sometimes hit in Arlington – China Garden. If you are ever in the neighborhood, you should go there for dim sum on weekends – but you have to get there by 11 am or forget getting a table.