In a large skillet with a lid, heat 2 tablespoons EVOO, 2 turns of the pan, over medium-high heat. Add the onion and cook, stirring, for 4 minutes, then stir in the kale and crushed red pepper; season with salt, pepper and a few pinches nutmeg. Pour in 1 cup chicken stock, cover and simmer for 10 minutes. Uncover the pan and stir in the radishes and half of the lemon juice.
While the kale is cooking, in another large skillet, heat the remaining 1 tablespoon EVOO, 1 turn of the pan, over medium-high heat. Season the salmon with the Old Bay, add to the skillet and cook, turning once, until cooked through, about 5 minutes. Sprinkle the remaining lemon juice on the salmon.
In a medium saucepan, combine the remaining 1 1/4 cups chicken stock, the butter and 1/2 teaspoon salt, cover and bring to a boil. Stir in the couscous and dill. Remove from the heat, cover and let stand for 5 minutes. Fluff with a fork.
Serve the salmon fillet on top of the kale, with the couscous alongside. Top the couscous with the cucumber.