Heat your oven to 450ºF
Line a baking dish with foil. Add the beets (trim off any leafy greens), then cover tightly with more foil. Roast for 45 minutes to 1 hour, or until the beets can be easily pierced with a fork
Let the beets cool to the touch, then peel and cut into a large dice. Refrigerate until ready to use
Arrange the arugula over a large serving platter. Top with the beets and oranges
In a measuring cup, combine the onion, oil, vinegar, lime juice, and cilantro. Season with salt and pepper. Pour the dressing over the salad. Let sit 5 minutes before serving
