In large bowl, combine giardiniera, olives, pepperoncini, celery, parsley, 1 tablespoon oil, and 1/8 teaspoon freshly ground black pepper. Toss until well.
Use serrated knife to cut bread in half horizontally. With fingers, remove most of center of bread, leaving 1 inch of bread all around crust. Reserve center of bread for another use.
Drizzle 1 tablespoon oil all over cut sides of loaf. Layer salami and ham on bottom half of bread. Top with giardiniera mixture, then cheese. Cover with top half of bread, pressing top down. Use serrated knife to cut sandwich into quarters. Sandwiches can be wrapped tightly and refrigerated up to 1 day.