- With the rack in the middle position, preheat the oven to 300°F (150°C).
- In a glass baking dish, rub the salmon pieces with the salt and sugar. Coat with the oil.
- Bake skin side down for about 25 minutes, depending on the thickness, or just until the fish is flaky. Remove the skin.
- Meanwhile, in a bowl, combine the kohlrabi with the salt and sugar. Let sit for 15 minutes at room temperature. Drain well. Return to the bowl and add the remaining ingredients. Stir well.
- In a small bowl, combine all the ingredients. Season with salt and pepper.
- When ready to serve, divide the yogurt sauce among four plates. Top with the slaw and salmon.