Season the pork shoulder thoroughly with cumin, dried oregano, sea salt, and black pepper.
Place the seasoned pork in a slow cooker and add the minced garlic, orange juice, and lime juice.
Cover and cook on low for 8 hours or high for 4 hours until the meat is tender enough to shred with a fork.
Remove the pork from the slow cooker and shred it using two forks, discarding any large pieces of excess fat.
For authentic crispy edges, sear the shredded pork in a non-stick skillet over medium-high heat for 3 to 5 minutes until golden.
Warm the corn tortillas in a dry skillet over medium heat for 30 seconds per side until soft and pliable.
Divide the shredded pork evenly between the two warm tortillas.
Top each taco with diced red onion, chopped fresh cilantro, sliced radishes, and a dollop of Greek yogurt before serving.