In a mixing bowl, combine the olive oil, orange juice, lime juice, white vinegar, minced garlic, ground cumin, dried oregano, smoked paprika, cayenne pepper, salt, and pepper. Whisk together until fully blended.
Add the pork shoulder cubes to the marinade and mix until well-coated. Cover the bowl with plastic wrap and let it marinate in the refrigerator for at least 1 hour, or up to overnight for deeper flavor.
Preheat the grill to medium-high heat.
Remove the pork from the marinade and thread it onto skewers (if using wooden skewers, soak them in water for 30 minutes prior to avoid burning).
Place the skewers on the grill and cook for about 8-10 minutes, turning occasionally, until the pork is nicely charred and reaches an internal temperature of 145°F.
Remove the skewers from the grill and let them rest for a few minutes.
Garnish with fresh cilantro leaves before serving.