Peel and then generously coat the beets with 2 tablespoons of grapeseed oil and put on a sheet pan or cookie sheet. Roast until they are tender, about 20 to 25 minutes. The beets are finished roasting when the exterior is tender to the touch.
In a medium bowl, add the vinegar, mustard, honey and sesame oil and whisk until blended. Slowly add the remaining 2 tablespoons of grapeseed oil and whisk until emulsified. Season, to taste, with salt and pepper. In a large bowl, combine the shredded cabbage mixture and spinach. Heat a medium saute pan over high heat, add 2 tablespoons of the dressing and all of the cabbage and spinach mixture. Toss until the mixture is slightly wilted and well coated with the dressing. Remove from the heat to a large platter. Slice the beets into 1/4-inch disks and stack alongside the cabbage and spinach mixture, alternating the beets and goat cheese. Drizzle with the remaining dressing and serve.