In a small bowl, whisk together the lemon juice and salt until the salt dissolves. Gradually pour in the olive oil while whisking to form a smooth dressing. Set aside.

Place diced beets in a large mixing bowl. Drizzle half of the vinaigrette over the beets and gently toss to coat. Marinate for 5-10 minutes.

Wash and slice the cucumber into thin rounds and add to the bowl with marinated beets.

Just before serving, crumble feta over the beet and cucumber mixture and add the dill.

Gently toss the salad, drizzle with remaining vinaigrette, and serve.

Transfer to a serving platter and enjoy immediately or refrigerate for up to three days.