In 12-inch skillet cook beets and potatoes, covered, in hot oil over medium heat for 10 minutes, turning occasionally. Uncover and cook 10 to 15 minutes more or until tender and brown on all sides, turning occasionally. Add peas to vegetables in skillet; sprinkle with salt and pepper. Cover and cook 2 to 3 minutes or until peas are crisp-tender.
Add reserved beet greens, cilantro, and lemon juice to skillet; toss to coat. Serve with lemon wedges. Makes 6 side-dish servings.