Venetian Tea Sandwiches Tramezzini

Name: Venetian Tea Sandwiches (Tramezzini)
Ingredients: 12 slices white sandwich bread; 3⁄4 cup mayonnaise; Kosher salt and freshly ground black pepper, to taste; 5 oz. canned tuna in olive oil, drained and flaked; 1⁄3 cup pitted black olives, halved; 2 tsp. capers, rinsed; 6 asparagus spears, blanched and halved lengthwise; 2 hard-boiled eggs, sliced; 1 medium tomato, cored, sliced; 6 oz. thinly sliced bresaola; 2 oz. thinly shaved parmesan; 1 cup baby arugula leaves