In a small saucepan, combine the balsamic vinegar, bay leaf, and sprig of rosemary. Bring to a boil and reduce until syrupy, about 1 tablespoon. Be careful — this happens quickly and can burn easily at the end. Let cool slightly while you make the dip and discard the bay leaf and rosemary sprig.
In a blender or food processor, combine the Genova Albacore Tuna and reserved oil, mayonnaise, capers, anchovies, and lemon juice. Process to make a smooth dip. Transfer to a flat serving bowl (you want a larger surface area to drizzle with the balsamic). Drizzle with the balsamic syrup and serve surrounded by crudités.