Preheat oven to 400.
Chop beet roots off from the greens. Rinse them and wrap them tightly in foil.
Place on baking sheet and roast for 1 hour.
Remove beets from oven and allow to cool. You may do this bit a day ahead and store the beets wrapped and chilled in the refrigerator.
Wash beets greens and kale well, rinsing away any grit.
Chop greens fine. Stems may be chopped small too. Otherwise compost them or save them to make vegetable stock.
Heat olive oil in a large skillet over medium-high heat. Add pepper flakes. When they start to sizzle, add greens by the handful. Cook, stirring, for about 5 minutes, or until greens wilt.
Grate in ginger and orange zest. Stir in orange juice.
Add cranberries and mix together gently.
Place greens and cranberries in a bowl or serving platter.
Toast walnuts at 400 degrees for 8 minutes, or until brown and fragrant.
Meanwhile, unwrap beets. The skins should slip away easily. Dice beets and scatter atop greens.
Top with walnuts and optional feta.