Combine the vinegar, oil, maple syrup, mustard, ¾ teaspoon salt, and ½ teaspoon pepper in a small jar and shake well.
Toss the roasted sweet potatoes and beets with about 1/3 of the dressing.
Place the kale in a large bowl, top with the remaining dressing and, with clean hands, massage the dressing into the kale for 2-3 minutes. Put in a serving bowl and top with sweet potatoes, beets, garbanzo beans, and pepitas.