For an easy way to wash kale, swish it around in a large bowl of water with 1 tablespoon salt, then rinse. The abrasive action of the salt works to remove grit.
Heat oil in skillet over medium-high heat. Sauté onion in oil 5 minutes, or until softened. Stir in garlic and red pepper flakes.
Add 6 cups kale, and cook 2 minutes, or until wilted, tossing occasionally. Add remaining kale, tomatoes, broth and salt. Cover, and bring to a boil. Reduce heat to medium, and simmer 15 minutes, or until soupy, tossing occasionally. Stir in beans and olives.
Cook spaghetti according to package directions. Drain, and return to pot with kale mixture. Cook 2 minutes over medium heat, or until pasta absorbs most of liquid. Sprinkle with Parmesan, and season with salt and pepper.