1. In a large bowl, whisk together zest, juice, tamari, honey, garlic, rosemary, and red pepper. Add pork tenderloins and marinate in refrigerator for at least 1 hour, up to 8 hours, turning occasionally.
2. Heat oven to 400°. Remove pork from marinade and place on a foillined baking sheet. Reserve marinade. Season pork with salt and pepper to taste. Roast until it reaches an internal temperature of 145°, 35–40 minutes.
3. Strain marinade into a saucepan and bring to a boil. Reduce heat, whisk in cornstarch, and simmer until reduced and thick, 10–15 minutes. Serve pork sliced with tangerine-herb sauce on the side.