1. Cut the ciabatta loaf in half lengthwise.
2. In a mixing bowl, combine mayonnaise, red wine vinegar, oregano, garlic powder, salt, and black pepper.
3. Spread the mayonnaise mixture on both halves of the ciabatta bread.
4. Layer the shredded lettuce, red onion, pepperoncini, black olives, tomatoes, salami, ham, and provolone cheese on the bottom half of the bread.
5. Place the top half of the bread on the sandwich and press down gently.
6. Cut the sandwich into 4 equal pieces and serve.