Whisk together fresh lemon juice and kosher salt in a small mixing bowl until dissolved, then drizzle in olive oil while whisking to combine.

Combine diced beets with half of the dressing in a large bowl and let marinate for about 5 minutes.

Chop cucumber into bite-sized pieces and fold them into the beet mixture.

Crumble feta over the mixture and fold in the dill, combining gently.

Drizzle the remaining dressing over the salad and toss gently to combine.

Transfer to a serving bowl and serve immediately or refrigerate for up to 30 minutes.