Combine soy sauce, sesame oil, grated ginger, and garlic in a large zip-top plastic bag. Add pork tenderloin to bag; seal. Marinate in refrigerator 1 1/2 hours, turning occasionally. Preheat grill to medium-high heat. Remove pork from marinade; discard marinade. Sprinkle both sides of pork evenly with kosher salt. Place pork on grill rack coated with cooking spray; grill 8 minutes. Turn pork over; grill 7 minutes or until a thermometer inserted into thickest portion of pork registers 145°. Remove from grill; let stand for 5 minutes. Cut crosswise into 12 slices.