Preheat the oven to 350 degrees F. Preheat the fryer. Build each sandwich by placing three slices of the salami and three slices of the Provolone cheese on one side. On the other side of the bread, place three slices of the mortadella and three slices of the Swiss cheese. Sprinkle each half with the banana pickles. Drizzle each sandwich with olive oil. Place the sandwiches on a sheet pan and place in the oven. Cook the sandwiches until the cheese melts, about 3 to 4 minutes. Place the shoestring potatoes in the hot oil and fry until golden brown, about 3 to 4 minutes. Remove the fries from the oil and drain on a paper-lined plate. Season the fries with salt and pepper. Remove from the oven and press the two halves together. Serve the grinders with french fries.