Place beet in a saucepan, cover with water, and bring to a boil. Reduce heat and simmer until beet is cooked through, about 30 minutes. Drain and allow to cool.

Peel beet and cut into 1/4-inch thick slices. Cut out red hearts using a heart-shaped cookie cutter.

Place salad greens in a bowl. Drizzle with olive oil and season with salt. Add beet hearts to the salad and toss. Arrange a couple of red hearts on top of the salad for serving.