Preheat oven to 400°F.
Toss sweet potatoes with 1 Tablespoon of oil in a bowl. Season to taste with salt and pepper, and arrange evenly onto a baking sheet.
Bake in the preheated oven until the sweet potatoes are tender, about 25-30 minutes. Let cool on the counter for a bit then transfer to the refrigerator to cool more.
While the potatoes are roasting, bring quinoa and 1 cup of water to a boil in a saucepan. Reduce heat; cover and simmer for 15 minutes, or until liquid is absorbed. Once cooked, allow to cool, then transfer to the refrigerator to cool more.
Meanwhile, heat the remaining 1 Tablespoon of oil in a large skillet over medium heat. Cook the onion and garlic, stirring frequently, until the onion has caramelized to a golden brown. This should take about 15 minutes. Stir in the kale, cooking until wilted, bright green and tender. Transfer the kale mixture to a bowl, and cool to room temperature in the refrigerator.
Once all the ingredients have cooled (at least 30-60 minutes), combine the sweet potatoes, kale and onion mixture, red wine vinegar, fresh thyme and nutmeg in a large bowl. Season to taste with sea salt and ground pepper. Gently stir to combine and serve.