Move over, Don Rockwell. There’s a new epicurean discussion board in town. If you can’t get enough of Washington Post restaurant critic Tom Sietsema between his dining column, travel column, or weekly “Ask Tom” online chats, then you might want to take a seat at Sietsema’s Table. Sietsema’s Table is the newest addition to the Post’s series of online discussion groups. Anyone with a washingtonpost.com account can sign in and join the group. Each week,…