Chop garlic, orange rind and 2 tablespoons oregano in mini-chopper or by hand. Score pork skin with sharp knife to make repeating diamond pattern. Make several ¾” deep cuts into the meat, working in score lines. Press garlic mixture into cuts. Place pork in 2-gallon food storage bag. Add Mojo Criollo marinade, push out all air and seal. Refrigerate for 24 to 48 hours.
Preheat oven to 450° F. Place pork, fat-side up, in 9”x13” baking dish or small roasting pan. Add water to come ½” up sides of pan. Roast, uncovered, for 30 minutes.
Reduce oven temperature to 325° F. Cook 3 to 3½ hours longer, or until internal temperature reads 180° F on instant read thermometer. (Your total cooking time will be about 25 minutes per pound). Check hourly, adding additional water to pan if needed. When done, place roast on cutting board and let rest for 15 minutes before slicing. Remove crispy skin from pork; chop into bite-size pieces. Garnish serving plate with fresh orange slices and fresh oregano leaves, if desired.
Place pan juices into fat separator. (You should have about 1¾ cups juices; add water or reduce if needed.) Pour juices into medium saucepan. Add shallot and simmer 4 minutes. Gradually whisk in flour until blended. Add 1½ teaspoons finely chopped oregano. Simmer 2 minutes or until thickened. Stir in vinegar and serve with pork and crisped skin.
Shred leftover meat and use in tacos or Cuban sandwiches.