Beet greens are identical to chard. Some varieties are grown for their roots, some for their greens. Use beet greens as you would chard; they are a good source of folic acid.
A favorite recipe is beet greens or chard with canned tuna on pasta. Clean and stem the greens. Cook the stems in boiling water until tender, about seven minutes. Blanch the leaves for a minute. Chop leaves and stems and saute with some olive oil along with minced garlic, diced onions, and chopped Kalamatas or dried black olives to taste. When the stems, leaves, and olives are nicely married, add one or two drained tins of tuna in water (don’t use tuna canned in oil) and mix until all is warm. Add in as much red wine wine vinegar as you like. Add salt and pepper to taste. Use this as a pasta sauce. It’s great on whole wheat linguine.