Preheat the oven to 400 degrees. Line 2 sheet pans with parchment paper.
Place the bread in the bowl of a food processor fitted with the steel blade. Process until the bread is in medium crumbs. Transfer the crumbs to a small bowl and add the milk. Set aside for 5 minutes.
In a large mixing bowl, combine the turkey, sausage, prosciutto, bread mixture, parmesan, parsley, oregano, red pepper flakes, 1 tablespoon salt, and 1 1/2 teaspoons pepper. Lightly combine the ingredients with your hands. Add the eggs, and stir lightly with a fork to combine.
With your hands, or an ice cream scoop, lightly roll the mixture into 2-inch-round meatballs and place them on the prepared sheet pans. Brush the meatballs with the olive oil. Bake for 30-35 minutes, until the tops are browned and the centers are completely cooked. Keep the oven on for the bread!
Pour the marinara sauce in a large, low pot, add the meatballs, and bring to a simmer. When heated through, top with the fresh mozzarella, and cover fora. few minutes, allowing it to melt.
Meanwhile, slice the ciabatta loaf in half lengthwise, leaving a top and bottom. Drizzle the bread with a generous coating of olive oil, and bake in the 400 degree oven for 5-7 minutes until lightly toasted.
To assemble, spoon the meatballs and sauce onto the ciabatta with the melted cheese on top. Ideally you will make two slabs of open faced sandwiches. Top with fresh basil and extra red pepper flakes as desired. Slice into servings and enjoy!