Wash the large potatoes thoroughly under cold water. In a large pot, cover the potatoes with salted water, bring to a boil, and simmer for 15 to 20 minutes until fork-tender.

Drain and cool the potatoes. Once cool, peel and cut into bite-sized cubes.

Wash the medium cucumber, slice it in half lengthwise, scoop out the seeds if large, and chop into bite-sized pieces.

In a mixing bowl, combine sour cream, chopped fresh dill, and freshly squeezed lemon juice. Season with salt and pepper to taste and whisk until creamy.

In a large serving bowl, gently mix the cooled potato cubes and chopped cucumber. Pour the creamy dill dressing over and fold gently.

Cover with plastic wrap or a lid and chill in the refrigerator for at least 15 minutes.