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