Preheat oven to broil or 425°F.
Slice the Italian loaf lengthwise and bore out some of the bread from the top to make room for fillings.
Spray or drizzle the inside of the bread with olive oil and sprinkle with garlic salt.
Layer provolone slices on both sides of the bread. Place in the oven until cheese is melted.
Remove from oven and add soppressata to one side and pepperoni to the other. Return to the oven until the pepperoni is slightly crisp.
While the sandwich is in the oven, make the grinder salad. Combine iceberg lettuce, red onion, and pepperoncinis in a bowl.
Add mayo, red wine vinegar, salt, black pepper, red pepper flakes, and oregano. Toss until well coated.
Remove sandwich from oven. Add the grinder salad on top of the meats.
Finish with sliced tomatoes, a drizzle of olive oil, and a sprinkle of salt and pepper.
Close, cut, and serve.