Finely chop a mixture of green and black olives, pickled vegetables, capers, garlic, parsley, and celery. Combine in a mixing bowl with olive oil and red wine vinegar. Season with oregano, black pepper, and red pepper flakes. Marinate for at least 1 hour, preferably overnight.

Slice the sesame-crusted round loaf in half horizontally and scoop out a small amount of the inner bread to create a hollow center.

Spread half of the olive salad over the bottom half of the bread. Layer with mortadella, capicola, and Genoa salami. Add provolone and mozzarella cheeses, followed by the remaining olive salad.

Place the top half of the bread over the filled bottom half and press down gently. Wrap tightly in plastic wrap and refrigerate for at least 1-2 hours.

Remove from the refrigerator, unwrap, and cut into wedges. Serve cold or wrap in aluminum foil and heat in a preheated oven at 350°F (175°C) for about 15 minutes.