Thaw scallops, if frozen. Rinse the scallops; pat dry with paper towels. For vinaigrette, combine basil, vinegar, lemon juice, oil, mustard, and ¼ teaspoon ground pepper in a screw-top jar. Cover and shake well; set aside.
Sprinkle the scallops with the remaining ¼ teaspoon ground pepper. Coat an unheated large nonstick skillet with cooking spray. Preheat over medium-high heat. Add the scallops. Cook for 2 to 4 minutes or until the scallops are opaque, turning once halfway through cooking.
Meanwhile, divide salad greens among four serving plates. Combine tomatoes, bell pepper, corn, and cucumber in a large bowl. Add half of the vinaigrette; toss to coat. Add to serving plates with greens. Add scallops to the salads and brush with some of the remaining vinaigrette. Pass the remaining vinaigrette. If desired, sprinkle with Parmesan.