Cut out the center core of the Brussels sprouts and remove as many of the fresh outer leaves as you can for the salad. Save the remaining part of the sprout for another use. Arrange the leaves as the base of the salad.
Remove the stem and root ends and peel the kohlrabi. Slice into matchsticks using a julienne tool or a very sharp knife.
Core the apple, but leave the peel on for colour and fiber. Slice into matchsticks or use a julienne tool. Toss with 1 tablespoon lemon juice to prevent browning.
Arrange the kohlrabi and apple on top of the sprout leaves and sprinkle with hemp hearts.
Whisk the vinaigrette ingredients together and drizzle over the salad just before serving.