1) Place the pork, fat side up, in a roasting pan fitted with a rack insert, and using a sharp knife, score the surface of the meat with small slits. Prepare the adobo: In a food processor, add the garlic, oregano, coriander, cumin, salt, and pepper. Add lime juice and orange juice. Drizzle in olive oil and pulse until you have a nice puree. Rub the marinade all over the pork, being sure to get into the incisions so the salt can penetrate the meat and pull out the moisture - this will help form a crust on the outside when cooked.
2) Preheat the oven to 150C/Gas 3.
3) Roast the pork for 3 hours, uncovered, until the skin is crispy-brown. Let the meat rest on a cutting board for 10 minutes before slicing, covered lightly with aluminium foil. Drizzle with lime juice and garnish with coriander.