MAKE THE MARINADE: Pour the orange juice, white vinegar, lime juice and honey into a resealable gallon-size bag. Add the garlic, cumin, paprika, salt, red pepper flakes and black pepper. Seal well and shake to combine.
PREP THE PORK: If needed, remove any silverskin from the tenderloin. Cut the pork into 1-inch cubes. Add the cut pork and onion to the marinade, making sure to seal well.
MARINATE: Let the pork marinate for 4 to 8 hours in the fridge or in a cooler on ice.
PREP THE GRILL: When ready to grill, prep the grill for indirect grilling, around 375° to 400° F. Divide the tenderloin into four Reynolds Wrap® Heavy Duty Foil packets, folding up the edges to seal in the juices. Pinch the tops shut.
GRILL: Place the foil packets over the grill and allow to cook for 10 minutes in the foil packets. Carefully open the packets, rotating if needed based on your heat source, and allow the pork to cook 10 minutes longer.
SERVE: Remove the pork bites, in their packets, from the grill once they reach 145° F. Allow the pork to cool in the packets for 5 minutes. Serve with toothpicks as an appetizer or as individual portions with desired sides if using as a main dish.