Pulse ¼ cup onion, garlic, oregano, and parsley together in a food processor, adding oil in a drizzle and scraping down sides as necessary, until the mixture is pasty, or use a mortar and pestle to grind the spices.
Mix cumin, chili, Sazon Goya, and paprika in a small bowl. Set aside.
Remove the pork roast from the packaging and gently rinse it under cold water.
Dry with a paper napkin or towel. Salt and pepper according to preference – a ½-¾ teaspoon per pound. Score the fat covering if desired.
Then do your best to rub the oregano and garlic mixture into the scoring or crevices. Refrigerate the pork shoulder for 4 hours or up to 3 days before roasting.
When ready to roast, remove the roast from the fridge and let it rest for about 30 minutes to come to room temperature.
Preheat the oven to 275℉/135℃. Cover a roasting pan with foil, then layer sliced onions and sliced orange on the bottom of the pan. Pour in about ½ cup of orange juice and ½ cup of stock or water.
Add any remaining marinade. You might have to add some more liquid as it cooks if you want more sauce to serve on the side.
Place pork skin side up in the pan. Remove any seasonings stuck to the top of the pork skin.
Roast the pork for about 3 hours, uncovered. Remove from the oven and increase the oven temperature to 500℉/260℃.
Place the roast back in the oven for 15-20 minutes until the skin is crisp and puffy, rotating the pan every 5 minutes for even crispness.
The internal temperature should be 180-185℉/80-85℃ on an instant-read thermometer.
Let the meat rest for 10-15 minutes before slicing; the meat should be tender. Serve with lime and sauce from the marinade.
If you want super crispy skin, just like you see in the picture. Place the pork roast on top of the roasting pan or a rack in a pan.