Lightly sprinkle 1 tablespoon black pepper over each tenderloin on all sides. Heat 2 tablespoons extra virgin olive oil in a large pan over medium heat. Increase the heat to medium-high and sauté the pork 6 minutes, turning to brown evenly. Lower heat to medium-low and sauté another 4 minutes on each side. The resulting meat is medium-rare.
Make a small cut with a sharp knife to check for desired doneness. Slightly undercook, as it will continue to cook while you prepare the sauce.
In a small saucepan of boiling water, gently boil the orange zest for 15 minutes to soften. Cool and cut the orange zest into thin matchsticks. In a large pan, sauté the carrots, onion and celery in butter for 5 minutes.
Add the orange strips, vinegar, orange juice, sugar and wine. Boil over low heat for 15 to 20 minutes until it reduces and thickness. Add 1 teaspoon of the dill, sprinkle in the flour and stir to combine and thicken slightly. Slice each warm tenderloin in slices and place on top the orange sauce.