This vegetarian sandwich can be made with almost any kind of cheese or bread.
Combine first 4 ingredients. Cut the bread loaves in half horizontally, and spread the mayonnaise mixture evenly over the cut sides of bread. Arrange 2 tomato slices over bottom half of each loaf; top with 3 tablespoons sprouts, 1 cheese slice, and 5 arugula leaves. Top with remaining bread halves, and serve immediately.