Slideshow: More Tasty Sandwiches
Brush the cut sides of the ciabatta with the olive oil and season with salt and pepper. Layer the prosciutto, artichoke hearts and arugula on the ciabatta and close the panini.
Set a large cast-iron skillet or griddle over moderately high heat. Arrange the panini in the skillet and weight them down with a smaller pan. Cook the panini until the outside is crisp and the filling is heated through, 3 minutes per side. Cut the panini in half and serve at once.