Simmer the pork in a large Dutch oven over high heat by combining the pork, garlic, sea salt, freshly cracked black pepper, and 8 cups of water. Cover and bring to a boil. Reduce the heat to medium-low and simmer covered for 45 minutes. Drain well and wipe out the Dutch oven.
Finish cooking the pork in the same Dutch oven, and heat the olive oil over medium-high heat. Add pork, ½ cup fresh orange juice, and ½ cup milk, then cook, stirring occasionally, until liquid has evaporated and the pork has browned, about 8 to 12 minutes. The pork will start browning after the liquid has evaporated. Season well with sea salt and pepper, to taste.
Cook the tortillas over an open gas flame for 15-20 seconds on each side, or wrap in a towel and microwave for 30 seconds, until pliable.
Serve the pork carnitas in the warmed corn tortillas with cilantro, red onion, guacamole, salsa, sour cream, cotija cheese, and fresh lime wedges. Enjoy.