To prepare dressing, combine first ten ingredients in a large bowl and whisk until thoroughly combined. Makes about 3/4 cup dressing.
To prepare salad, wash beets well, being careful not to break open their skins. Cut off the tops, leaving a stalk of about 1 1/2 inches. Reserve green tops and set aside.
Place beets in a 3-quart sauce pan, cover with cold water and bring to a boil. Reduce heat to medium, cover and cook until a knife can be easily inserted and removed, about 30 minutes. Remove from heat and allow to cool in cooking water. Slip off the beef skins, trim off the tops and cut the beets into bite-size pieces.
Toss beets and tomatoes with 1/4 cup of the dressing. Set aside to marinate. Wash greens. Transfer greens with some water still clinging to the leaves, to a large pot over high heat. Cook, stirring, until just wilted but still bright green, about 4 minutes. Drain greens and squeeze out excess moisture. Cool slightly and chop coarsely. Transfer greens to a medium bowl. Add 1 tablespoon of the dressing and toss to coat. Season greens with salt and pepper. Arrange tomatoes and beets in the center of a platter and surround with greens. Garnish with cilantro. Pass remaining dressing separately.