Place cucumber slices in a colander over a bowl and sprinkle with salt and toss, let sit for ~20 minutes or until they lose some of their water. Remove cucumbers, squeeze and blot dry with paper towels.

In a large bowl, mix sour cream and vinegar until combined. Stir in red onion, garlic and dill. Add cucumbers and stir to combine. Season with black pepper to taste (optional). Refrigerate, covered, at least 1 hour before serving.