How to Make It
Preheat the oven to 400°. In a nonreactive 13-by-9-inch baking dish, combine the beets, thyme sprigs, garlic, white wine, orange juice and a pinch of salt. Cover with foil and bake for about 1 1/4 hours, or until the beets are tender. Let cool slightly, then peel the beets and cut them into 1-inch dice. Discard the cooking liquid.
In a large bowl combine the oil, vinegar, orange zest and minced thyme. Add the beats, season with salt and pepper and toss with the dressing. Toss the beets with the arugula, transfer to a platter and sprinkle the ricotta salata on top.