Mix marinade, mustard and oregano in large resealable bag. Add pork; turn to coat well. Massage pork and marinade for 4 to 5 minutes.
Remove pork from marinade. Thread pork onto long double skewers. Discard any remaining marinade.
Grill pork over medium-high heat 4 minutes per side or until internal temperature reaches 145°F to 150°F. Let stand 5 minutes before slicing.