This dish needs three hours to marinate.
Trim and cut pork into 2-inch chunks; there is a certain amount of waste. Chop the 1/2 large onion. Combine crushed garlic, chopped onion, orange juice, lime juice, 1/4 cup olive oil, cumin, oregano, and salt to make a marinade. Pour over the pork cubes and marinate for about 3 hours.
Remove meat from marinade and rinse off. Strain marinade; discard the solids. Place the strained marinade in a measuring cup and add enough water to bring the total up to 2/3 cup liquid (5.33 fl.oz.). Place the pork, liquid, and another 1/4 cup olive oil in a saucepan wide enough to hold the pork pieces in a single layer (we use a Dutch oven). Simmer uncovered until all the water boils away (about 20 minutes) and only the fat remains. (The water is gone when the pork starts taking on color.)
Meanwhile slice the 3 ounces of onion.
Finish browning the pork in the remaining fat until just nicely colored taking care not to overcook. Remove the pork pieces and keep warm. Add the sliced onion and cook briefly until wilted and golden.
Serve the pork and onion slices, garnished with lime wedges. White rice and plantains are the suggested accompaniments. Brown rice is OK too. Because of the dryness of this combination, best served with a moist vegetable such as a sweet pepper sauté.
Serves 2, with leftovers
Masitas de Puerco, adapted for the leaner pork sold these days
http://macheads2.net/recipes/MasitasDePuerco.html