As Americans, we have been conditioned to accept cut-rate Chinese in cardboard boxes. Hunan Coventry treats diners to a more refined taste of the Orient. The dining room is as spacious as it is refined, serviced by well-dressed, polite waiters. The menu boasts a wide selection of entrées that employ standard ingredients to spectacular effect. The Hunan chicken is a medley of baby corn, green and red peppers, water chestnuts, and thick, succulent pieces of white meat, swathed in a sauce just spicy enough to activate your endorphins. And the General Tso's, a house specialty, sautées boneless chicken in minced scallions and hot peppers to create a dish that's a far cry from the lifeless, overfried version served at corner joints.