Preheat the oven to 400 degrees F and a grill pan over medium-high heat.
Sprinkle the pork tenderloin generously with salt. Coat the preheated grill pan with oil. Sear the tenderloin on all sides until golden brown and internal temperature reaches 145 F, about 10 minutes. Remove from heat and allow to rest for 5 to 7 minutes. Cut into 1/4-inch-thick slices.
Toast the rolls, cut side-down, on the grill pan allowing the bread to crisp up and soak up the flavor from the pork. Remove from heat and set aside.
Meanwhile, whisk together the mayonnaise, Parmesan, Calabrian chiles and vinegar in a small bowl.
Bring a large pot of salted water to a boil. Fill a large bowl with salted water and ice. Add the broccoli rabe to the boiling water and cook until just tender, about 1 minute. Remove from boiling water and drop immediately into the ice bath. Once cool, remove, drain and roughly chop.
Coat a large skillet with oil and heat. Add the garlic and cook, stirring, until just soft, about 1 minute. Add the broccoli rabe, season with salt and saute until heated through.
Build the sandwiches: Spread the mayonnaise-chile mixture on the toasted sides of a roll. Top the bottom of the roll with half the pork, broccoli rabe and provolone cheese. Top with top piece of the roll and transfer to a baking tray. Build the second sandwich with the remaining ingredients. Bake just until cheese melts, about 3 minutes.