Combine vinegar, mustard, 1 tablespoon oil, 1/4 teaspoon salt, and pepper in a small bowl, stirring with a whisk. Set aside.
Combine Caribbean seasoning, remaining 1/4 teaspoon salt, and shrimp in a large bowl; toss well. Heat remaining 1 tablespoon oil in a large nonstick skillet over medium-high heat. Cook shrimp 3 to 4 minutes per side or until done.
Combine greens and next 3 ingredients in a bowl. Add dressing, tossing gently to coat. Divide salad among 4 plates. Top with shrimp.