Cook pasta according to package instructions until al dente. Drain and rinse under cold water to stop cooking.
In a large bowl, combine the cooked pasta, flaked crabmeat, celery, red bell pepper, red onion, peas, and green onions.
In a separate bowl, whisk together Greek yogurt, mayonnaise, Dijon mustard, celery salt, fresh dill, and lemon juice. Adjust the seasonings to taste.
Pour the dressing over the pasta mixture and toss to coat evenly. Season once more by adding salt and black pepper to taste.