Combine cranberries, water and orange peel in heavy medium saucepan. Bring to boil. Reduce heat and simmer until cranberries burst, stirring occasionally, about 10 minutes. Strain out cranberries and peel and transfer to processor. Puree until smooth. Add vinegar, shallots, sugar, salt and peppercorns and blend well. Gradually whisk in vegetable oil. Cool completely.
Pour marinade into large glass baking dish. Add tenderloins; turn to coat. Cover and refrigerate at least 8 hours or overnight, turning occasionally.
Preheat oven to 450 degrees F or prepare barbecue (medium high heat). Remove pork from marinade; discard marinade. Roast or grill pork until thermometer inserted into thickest part of tenderloin registers 150 degrees F. Transfer pork to work surface; let stand 5 minutes. Cut pork into 1 inch thick slices. Arrange on platter and serve.
c.1997, M.S. Milliken & S. Feniger, all rights reserved