Coarse or kosher salt and freshly ground pepper to taste
Using a knife carefully cut the skin and stems from the kohlrabi (the skin is very thick so a regular vegetable peeler won’t do the trick). Sliver or grate the kohlrabi (if grating, use the largest holes of the grater). Place it in a large bowl. Peel, core and sliver or grate the apples, then add them to the kohlrabi.
Place the ginger, mustard, olive oil, fish sauce, sesame oil and salt and pepper in a food processor fitted with the regular steel blade, or a blender, and processor until fully blended and smooth. Toss the slaw with the dressing, garnish with sesame seeds if desired, and serve.