Add Olive Oil, Orange Juice, Lime Juice, black pepper, salt, dried oregano, minced garlic, cumin, chili powder, and fresh chopped cilantro.
Mix well. Cover and marinade in the refrigerator for 2 hours.
Thread shrimp tail and head area on a bamboo skewer.
Heat grill. Set temperature on low.
Grill shrimp turning often and basting with remaining marinade. Cook until shrimp turn coral pink, are firm to the touch, with a slight golden brown char.