Boil pasta in salted water until al dente. Drain, rinse under cold water, and set aside.
Season shrimp with Cajun spice, salt, and pepper. Toss to coat evenly.
Heat olive oil in a skillet over medium heat. Cook shrimp for 2 minutes per side until opaque. Let cool slightly.
Chop tomatoes, bell pepper, celery, and onion while shrimp rests.
Whisk mayo, Greek yogurt, lemon juice, hot sauce, and garlic powder in a bowl. Adjust seasoning as needed.
Combine pasta, shrimp, veggies, and dressing in a large bowl. Toss everything together until evenly coated.
Chill for at least 30 minutes to let flavors blend. Or eat immediately if patience isn’t your thing.