1. Thaw scallops, if frozen. Rinse scallops; pat dry. Place scallops in a medium bowl.
2. For marinade, finely shred 1 teaspoon peel from the orange; set aside. Peel, seed, and section the orange and grapefruit over a small bowl to catch juices. Stir the orange peel, onion, jalapeno pepper, and garlic into the orange and grapefruit juices. Pour over scallops, stirring to coat. Cover and marinate at room temperature for 15 minutes. Drain scallop mixture, discarding marinade.
3. In a large skillet heat oil over medium-high heat. Add scallop mixture. Cook and stir for 1 to 2 minutes or until scallops are opaque. Transfer scallop mixture to another medium bowl; cool slightly. Drain and discard any liquid that has accumulated. Add the orange and grapefruit sections, mango, and mint to scallop mixture; toss gently to coat. Spoon into small bowls. If desired, garnish with additional mango.