Add all of the olive salad ingredients to a food processor and pulse until finely chopped and well combined. Set aside.
Preheat the oven to 350°F. Spray a 9×13-inch baking dish with cooking spray and set aside.
Slice the rolls in half horizontally, keeping them intact. Place the bottom half in the prepared baking dish.
Add the provolone in an even layer. Top with the capicola, salami, and mortadella. Using a slotted spoon to drain excess liquid, spoon the muffuletta olive salad evenly over the meats.
Place the top half of the rolls over the filling. Brush with melted butter and sprinkle with sesame seeds.
Cover loosely with foil and bake for 15 minutes. Remove foil and continue baking for 8 to 10 minutes, or until the tops are golden and slightly crisp.
Let cool slightly, then transfer to a cutting board and slice into individual sliders. Serve warm.