Prep the kohlrabi. Chop off the greens, and reserve for cooking or compost. Use a sharp knife to cut away all the thick skin. Cut the kohlrabi in half, then into several slabs that will yield bite size pieces. If you have a food processor, use the thinnest slicing setting to slice into very thin slices. Alternately use a knife or mandolin. Slice 4 cups of kohlrabi.
Place the kohlrabi into a large bowl with the onions and cilantro. Measure the vinegar into a cup, then add the honey and stir to dissolve. Toss the salad with the honey vinegar mixture and season with salt to taste. Serve at once or chill in the refrigerator. This salad will hold up to storing and is perfect for potlucks or picnics.