In a medium pot, put the farro and 3 cups of water. Bring to a boil, reduce the heat to medium-low, and simmer until tender, about 30 minutes. Drain excess water and place farro in a large salad bowl to cool.
While the farro cools, prepare the kale and kohlrabi. Remove the stem from the kale leaves and slice the kale thinly. Peel the kohlrabi and cut into matchsticks. Put the kale and the kohlrabi in the salad bowl, with the farro. Add the toasted cashews.
Now, make the vinaigrette. Mince the garlic. Add a generous sprinkle of salt and mash with a fork, until a paste forms. Place in a small bowl and add the Dijon, lemon juice, olive oil, and maple syrup. Season with sea salt and pepper, to taste. Whisk vigorously.
When ready to serve, season the salad with the vinaigrette and serve as a main course, in shallow bowls. Bon appétit!