In a small bowl, stir together the paprika, salt and pepper. Rub the paprika mixture all over the tenderloins. Transfer to a plate, cover and let stand at room temperature for 1 hour.
Preheat an oven to 375°F (190°C).
In a large, heavy ovenproof fry pan over high heat, warm the 2 Tbs. olive oil. When the oil is shimmering, add the tenderloins and sear on all sides, about 5 minutes total. Transfer the pan to the oven and roast the pork until an instant-read thermometer inserted into the thickest part of a tenderloin registers 135°F (57°C) for medium, 30 minutes, or until done to your liking. Remove the pan from the oven, transfer the pork to a carving board, and tent with aluminum foil. Let rest for 10 minutes.
Meanwhile, make the sauce: In a small nonreactive fry pan over medium-low heat, warm the 1/4 cup (2 fl. oz/60 ml) oil. Add the garlic and cook, stirring often, until light golden brown, about 4 minutes. Stir in the parsley and pepper flakes and cook for 10 seconds. Add the orange juice and simmer, swirling the pan once or twice, until slightly reduced, about 2 minutes. Season to taste with salt and remove from heat.
Cut each tenderloin crosswise into thick slices. Arrange the slices on a warmed platter or individual plates. Spoon the sauce over the pork and serve immediately. Serves 4.