Prepare the dressing. Whisk the mayonnaise, sugar, salt, black pepper, and Old Bay seasoning in a small mixing bowl until the mixture is smooth and well combined.
Cook the pasta. Cook the elbow pasta in salted boiling water for 1 minute less than the package instructions recommend (about 6 minutes for most brands). Then, drain and rinse the pasta under cold water to stop the cooking process. Set it aside to cool completely.
Combine. In a large mixing bowl, add the cooled pasta. Then, pour the dressing over the pasta and toss gently to coat. Next, add the diced cucumber, red bell pepper, red onion, and cooked shrimp. Stir everything together until evenly mixed and coated with the dressing.
Chill and serve. Cover the bowl with plastic wrap and refrigerate the salad for at least 2 hours or overnight for a deeper flavor. Serve chilled, and enjoy!