Preheat the oven to 425 degrees. Heat 1 tablespoon of the olive oil in a large ovenproof skillet over medium-high heat. Season the pork generously with salt and pepper and cook, turning, until browned on all sides, about 6 to 8 minutes. Transfer the skillet to the oven and cook the pork until a thermometer inserted into the thickest part registers 140 degrees, about 10 to 15 minutes. Transfer the pork to a cutting board and let it rest at least 5 minutes before slicing. Keep the pan drippings.

Toss the dates, orange juice, reserved pan drippings, 3 tablespoons chopped cilantro, and remaining 2 tablespoons olive oil in a small bowl. Season with salt and pepper. Spoon the relish over the pork and garnish with cilantro leaves.