Preheat oven to 425°F and line a baking sheet with parchment paper.
Toss Brussels sprouts with olive oil, salt, and pepper. Roast for 20-25 minutes, tossing halfway through, until browned and tender.
While the Brussels sprouts roast, prepare the pasta. Cook according to package directions until al dente. Drain and rinse under cool water.
Whisk together the pumpkin, olive oil, apple cider vinegar, Dijon, maple syrup, garlic, thyme, smoked paprika, salt, and pepper. If needed, add water, 1 tablespoon at a time, until smooth and pourable.
Add kale to a large bowl with a tablespoon or two of the dressing. Massage with your hands for about 30 seconds to soften it.
Add pasta, roasted Brussels sprouts, cannellini beans, sun-dried tomatoes, and pepitas. Pour over the remaining dressing and toss well.
Serve immediately or refrigerate and serve later. Add a splash of water or olive oil before serving if the pasta has absorbed too much dressing.