First, make the dressing. In a small bowl, whisk together the olive oil, apple cider vinegar, mustard, and maple syrup. Set aside. In a small saucepan, bring the quinoa and stock or water to a boil. Reduce the heat to low, cover, and cook until the water is absorbed, about 15-20 minutes. Meanwhile, heat the oil over medium heat in a large skillet. Add the apple and cook until softened, about 3-5 minutes. Add the garlic and cook an additional minute. Add the kale, lemon juice, and water and sprinkle with salt and pepper. Stir, then put the lid on the skillet and cook until the kale is wilted and tender, 5 minutes or so. Turn off the heat. When the quinoa is finished, stir it in the skillet with the apple and kale. Pour the dressing over the top and stir to coat. This salad is best served warm. Enjoy!