Combine the first eight ingredients for the salad in a medium bowl. Add the mango slices and toss to coat. Store in the fridge until the scallops are ready.
Heat the oil for the scallops in a non-stick skillet set over medium-high heat. Season the scallops with salt and white pepper, add them to the skillet, and cook 2 minutes per side, or until just cooked through. Sprinkle with lime juice and then remove from heat. Divide the leaf lettuce among four plates. Top with the mango salad and then the scallops. Garnish with lime slices and serve.