Bring a large saucepan of lightly salted water to a simmer.
Place the quinoa in a strainer and rinse well, then drain, and add to the simmering water.
Cook the quinoa until the grains are translucent and tender and the germ has spiraled out from the grain, about 15 minutes (be careful not to overcook).
Remove from heat and drain any remaining liquid.
Fluff the quinoa with a fork and transfer to a baking sheet to cool.
Note: the quinoa can be made ahead of time and stored, covered and refrigerated, up to 3 days before using.
In a large bowl, place the kale and one-fourth cup of the vinaigrette.
Using your hands, massage the vinaigrette into the kale until the kale is softened, 2 to 3 minutes.
To the bowl, add the cooled quinoa, the sunflower seeds, bell pepper, grapes and Parmigiano Reggiano, tossing to combine.
Divide the salad among serving plates, evenly sprinkling over the Manchego cheese and garnishing with the preserved lemon strips.