Preheat the oven to 450°. Soak the ancho chiles in warm water for 5 minutes; drain and set aside.
In a dish, combine 1 tablespoon cumin, the paprika, 1 tablespoon pepper and 2 teaspoons salt. Brush the tenderloins with 3 tablespoons oil and roll in the spice mixture until coated.
In a large ovenproof skillet, heat the remaining 3 tablespoons oil over medium-high heat until hot. Sear the pork, turning with tongs, until browned all over. Transfer the skillet to the oven and roast until an instant-read thermometer inserted in the thickest part registers 150°, 10 to 12 minutes.
Meanwhile, place the reserved chiles in a blender and add the coconut milk, peanut butter, broth, lime juice, 2 teaspoons salt, the coriander, the remaining 1/2 teaspoon cumin and 1/2 teaspoon pepper. Blend until the sauce is smooth.
Remove the skillet from the oven, transfer the pork to a cutting board and let rest for 5 minutes. Slice into 1/2-inch-thick medallions and arrange on a serving platter. Drizzle with the ancho-peanut sauce.