Heat panini press or cast iron skillet for pressing sammy. If using a skillet, you will need another heavy skillet to press with or a brick, wrapped in foil.
Flake tuna in bowl. Add chopped artichokes, sun-dried tomatoes, olives, caper berries or capers, parsley, shallots and arugula. Dress with lemon juice and liberal drizzle of EVOO. Mix to combine salad thoroughly, season with pepper to taste.
Arrange half of the cheese, overlapping the slices, on the bottom half of ciabatta. Top with salad in even layer then arrange remaining cheese and top with bread. Cut the loaf into 4 sections and press a few minutes to melt cheese and heat through. Serve sammies with Warm Penne Pasta Salad alongside.