Rub the pork shoulder evenly with ground cumin, dried oregano, sea salt, and black pepper.
Place the seasoned pork in a slow cooker and pour in the orange juice, lime juice, and minced garlic.
Cover and cook on low for 8 hours or high for 4 hours until the meat is tender and easily shredded with a fork.
Remove the pork from the slow cooker and shred it using two forks, discarding any large pieces of fat.
Heat the olive oil in a large skillet over medium-high heat and add the shredded pork in a single layer.
Press down with a spatula and cook for 3-5 minutes without stirring until the bottom is beautifully crispy and golden.
Warm the corn tortillas in a dry pan over medium heat for 30 seconds per side until soft and pliable.
Divide the crispy pork between the tortillas and garnish with diced red onion, fresh cilantro, and thinly sliced radishes.