Step 1Leaving 1 inch of stem and all of the roots, steam beets until they're tender-firm when pierced with a knife, 20 to 25 minutes. Let cool, then slip off skins. Cut beets in quarters or sixths.
Step 2Whisk lemon zest, juice, onion, salt and pepper to taste, coriander, parsley, mint, cilantro and oil in small bowl. Taste on a beet and correct seasonings, if necessary. Toss beets with enough dressing to cover lightly. Toss spinach with remaining dressing and arrange on salad plates. Add beets and olives and serve.