Preheat the oven to 400 degrees. Peel the sweet potato and then cut it into small, 3/4-inch cubes. Toss the cubes with the olive oil, thyme, and a pinch each of salt and pepper. Spread the seasoned sweet potato cubes out on a baking sheet covered with parchment paper. Roast the sweet potato in the preheated oven for about 35 minutes, or until the sweet potato is just barely golden brown on the edges (the exact time will depend on how large or small your sweet potato cubes are).
Meanwhile, tear the kale leaves from their woody stems. Take a handful of leaves at a time and chop them into thin strips (don’t stress about making this perfect, just try to slice it thinly). Place the sliced kale leaves in a colander and rinse well with water. Allow the kale to drain while the sweet potato finishes roasting (or use a salad spinner to dry the kale well).
Place the washed and well drained kale in a large salad bowl. Staring with just two tablespoons, add dressing to the kale and toss to coat. I used 1/4 cup of dressing total, but if you have a smaller bunch, you may want to use less. Make sure to stir well before adding more because it will take a bit to get the dressing to coat all of the curly bits of kale.
After the sweet potato has finished roasting, pile it on top of the dressed kale leaves. Sprinkle the sunflower seeds and cranberries over top as well. Serve immediately or refrigerate until ready to eat.