Combine all ingredients for the dressing into a bowl and whisk. Set aside.
Cut the kohlrabi halfway through, careful not to cut through the center. Spiralize the kohlrabi, using Blade B. Place noodles in a bowl with the radish noodles and shaved asparagus.
Pour dressing over the noodles and toss to combine thoroughly. If possible, let sit for 30 minutes – 1 hour (longer is better) for flavors to infuse the kohlrabi and radishes. If not, immediately transfer to a serving platter or bowl and top with sunflower seeds.