Prepare the marinade by combining the soy sauce, oil, vinegar, white pepper, cumin, coriander, garlic powder, onion powder, chili powder, paprika, oregano, smoked paprika, garlic, cilantro, and lime juice in a large dish or ziplock bag.
Add the flanken short ribs and make sure each rib is evenly coated with the marinade. Put it in the refrigerator to marinate for 6-24 hours.
Remove the meat from the refrigerator for 30 minutes before cooking.
Grill the flanken short ribs by heating a grill or grill pan over medium-high heat and coating with cooking spray.
Once HOT, lay a few short ribs on the grill pan and cook for 3-4 minutes, or until browned. Flip and continue to cook for 2-3 minutes, or until cooked to your desired degree of doneness.
Remove from the grill pan and set aside on a serving plate, then top with a loose foil tent. Finish cooking the remaining short ribs.
Optional: Boil the remaining marinade in a small saucepan with ¼ cup of water for 3-5 minutes, stirring often.
Pour through a fine sieve into a fat separator. Drizzle over the cooked meat.
Sprinkle the top with fresh cilantro and green onions.
Serve immediately with lime wedges on the side. Enjoy.