By Lenn Thompson, Executive Editor As good as local cabernet franc can be, it's not easy to define the "typical Long Island expression" of my favorite red wine grape. At this point in the region's growth, there are nearly as many styles of cabernet franc here as there are wineries producing them. Some wineries make their cabernet franc without any oak at all — while others use lots of newer wood to cover up and mask the telltale "green" character of the grape. Some wineries try to keep their franc juicy with nice acidity while others strive for a richer,…