1.Beat The Oil And Vinegar In A Small Bowl With A Fork Or Whisk. 2.Coarsely Mash The Beans And Tuna In A Medium Bowl With A Fork. Stir In The Onion And Half The Vinegar Mixture. 3.Brush The Rolls With The Remaining Vinegar Mixture. Divide The Spinach Among The Bottom Roll Halves. Top With The Tuna Mixture And The Remaining Roll Halves.