In a mixing bowl, gently combine the fresh lump crab meat with diced cucumbers, red bell pepper, and red onion.
In a separate small bowl, whisk together the mayonnaise, Dijon mustard, lemon juice, Old Bay seasoning, salt, and pepper until smooth.
Pour the dressing over the crab and cucumber mixture and toss gently until everything is evenly coated.
Taste and adjust the seasoning if needed.
Refrigerate the salad for about 10 minutes to allow the flavors to meld.
Serve chilled on individual plates or in a larger serving bowl, garnished with fresh parsley or dill if desired.
For a bit of spice, consider adding diced jalapeños or a splash of hot sauce to the dressing.
To lighten the recipe, you can substitute Greek yogurt for mayonnaise.
This salad is best enjoyed fresh but can be stored in the refrigerator for up to 24 hours.