Our personal trainer has been cursing Alejandro Luna for ages. That's because the former executive pastry chef at the Langham Hotel does things with chocolate that we'd never dared imagine. Now Luna is realizing a longtime dream and opening the doors to his own chocolate shop and wholesale business later this winter. Aroa Fine Chocolate (1651 Washington Street, Boston), named for a coastal town in Luna's native Venezuela that's home to one of the world's largest cocoa-bean plantations, will showcase Luna's passion for chocolate as an art form. A European-style shop with a modern feel, Aroa will feature three cases of goodies - chocolates, petit fours and small pastries, and desserts - plus pre-packaged "collections" of Luna's finest bon-bons. A window will peek in on the kitchen, and in addition to indoor seating for 12 to 15, an outdoor patio is expected to take shape come spring. We'll be on a strict diet until opening day.