Wash the beets well, wrap them in foil, and roast until tender and easily pierced with a fork. Roasting enhances sweetness and softens texture. Once cooled, peel and cut them into bite-sized cubes for easy mixing.
Wash the cucumber and slice it thinly or into half-moons. Keeping the peel gives extra color and crunch. Set aside while preparing the rest of the ingredients.
Whisk olive oil, lemon juice or vinegar, salt, and pepper in a small bowl. This simple vinaigrette adds brightness without overpowering the vegetables. Adjust seasoning to taste before adding to the salad.
Combine beets and cucumbers in a large bowl, then drizzle dressing over them. Toss gently to keep the pieces intact. Add feta and chopped dill last so they stay fresh and visible.
Place the salad in the refrigerator for about 15–20 minutes before serving. This allows flavors to blend together. Serve chilled or slightly cool for the best taste.