Brush tenderloin with oil. Rub salt and garlic onto meat. Place meat on rack in a shallow roasting pan. Roast in a 425 degree F oven for 25 to 35 minutes or until internal temperature registers 160 degree F on an instant-read meat thermometer.
Meanwhile, for salsa, in a food processor bowl combine plums, orange juice, sugar, jalapeno pepper, lemon juice, and ginger. Process with on/off turns until chopped. Transfer to a small saucepan. Cook, uncovered, over medium heat until heated through.
To serve, slice meat. Serve with warm salsa. If desired, garnish with oregano. Makes 4 servings.