To prepare pork, combine first 13 ingredients in a blender; process until smooth. Place green onion mixture in a large zip-top bag. Add pork to bag; seal. Marinate in refrigerator 8 hours or overnight, turning occasionally.
Remove pork from bag; discard marinade. Place pork on a grill rack coated with cooking spray; grill 23 minutes or until a thermometer registers 155° or until desired degree of doneness. Let pork stand 10 minutes. Slice pork into 1/2-inch-thick slices.
To prepare relish, combine pineapple and remaining ingredients in a bowl, stirring well. Serve with pork.