To make the dressing, combine the sour cream, lemon juice, sugar, dill, and salt in a bowl. Set the dressing aside.

Peel the cucumbers, if desired. Slice the cucumbers and thinly slice the red onions.

Combine the cucumber, red onion, and dressing in a large bowl and stir to combine.

Let the salad sit for 5-10 minutes, give it another stir, then serve.