The Upper West Side — flush with Dovetail’s success; the boffo business at Kefi , Cesca , and Ouest ; and with Fatty Crab II on the way — seems to be — of all places — the hot restaurant neighborhood du jour. And the next chef heading northwest? Tuscan toque Cesare Casella, who has a lease on a 1000-square-foot space on West 73rd Street. The Maremma chef, who leads the Italian program at the French Culinary Institute, is also seeking to acquire an adjacent storefront. “If we can do that, we will have an Italian restaurant, but not a Tuscan cowboy one,” Casella says. “I have to represent all of Italy, the way I teach at FCI. If we stay with the small space, it will be Bean Bar or something like it.” Bean Bar is the Tuscan takeout bean operation Casella has wanted to open at Grand Central since last May. His new space won’t be ready till fall or next winter at the earliest.