Prepare the Crab and Vegetables
In a large mixing bowl, add the chopped crab meat, celery, red bell pepper, red onion, and chives or green onion. Toss gently to combine.
Make the Dressing
In a small bowl, whisk together the mayonnaise, sour cream or Greek yogurt, Dijon mustard, and lemon juice until smooth. Add salt and pepper to taste.
Combine and Toss
Pour the dressing over the crab mixture and gently fold until everything is evenly coated. Taste and adjust seasoning as needed.
Chill and Serve
Refrigerate the salad for at least 15-20 minutes to allow the flavors to meld. Serve cold.