Slice each 3-inch slice of Ciabatta in half horizontally to make a top and a bottom piece. In a toaster oven, toast the bread for 2 minutes, or until lightly toasted. On one side of the bread, place 2 slices of the mozzarella. On the other piece of Ciabatta, place a slice of Brie. Place 1/4 of the corn on top of the Brie. Place 2 slices of tomato on top of the mozzarella. Season both sides of the panini with salt and pepper. Place the panini in the toaster oven and toast for 4 minutes, or until tomato is warm and cheese is beginning to melt. Remove from the toaster oven and top the tomatoes with some of the arugula. Drizzle with a little extra virgin olive oil. Press the 2 halves together. Slice in half. Repeat process for the other 3 sandwiches.