1. Place first 5 ingredients in a food processor; process until finely chopped. Slowly pour oil through food chute; process until smooth. Place fish in a shallow dish; rub mixture over fish. Cover and chill 2 hours.
2. Preheat grill to high heat.
3. Sprinkle fish with salt and black pepper. Place fish on a grill rack coated with cooking spray, and grill for 4 minutes on each side or until desired degree of doneness. Remove from grill. Break fish into chunks. Heat tortillas according to package directions. Divide fish evenly among tortillas.
Sustainable Choice: Wild-caught Alaskan halibut is the best option. If not available, opt for other U.S. or Canadian wild-caught Pacific halibut, or substitute striped bass or U.S. line-caught cod.