Preheat the oven to 350°F.
Cut the bread in half and place it on a sheet tray cut side up. Remove most of the inside of the bread leaving about ½ inch of the bread. Add half of the provolone to each side. Place in the oven until melted, about 5 minutes.
Layer the ham over one half of the sub, and layer the soppressata on the other side.
Top the ham with the salami. Top the soppressata with the pepperoni.
Place back in the oven to heat the meats through and toast the bread, for 5 minutes.
While the sub is baking, make the grinder salad. Whisk together the mayonnaise, vinegar, garlic, pepper, oregano, chili flakes, and salt until combined.
Add the pepperoncini and red onion, and stir around in the dressing until coated.
Add the lettuce, and using tongs toss it in the dressing to coat, set aside.
Sprinkle the sub with ¼ of the parmesan cheese. Add tomato slices. Drizzle the tomatoes with olive oil and add salt and pepper to taste.
Add some of the grinder salad. Top with the remaining parmesan cheese.
Add the top half of the sandwich over the bottom half. I like to press it down gently.
Cut into wedges and serve with more of the grinder salad on the side with chips for dipping!