To make vinaigrette: in a small bowl, whisk together lemon juice, olive oil, salt, and pepper until well combined.
To make salad: toss the pears with 1 tablespoon of the vinaigrette to prevent browning. Toss the beets and greens (if using) with the remaining vinaigrette. Add pepper and salt.
To serve, top the beets with sliced pears.
Serve and enjoy!