Preheat oven to 500°F. Place pizza stone on middle rack of oven, if using.Heat 2 Tbs. oil in large skillet over medium heat. Add onions, and cook 10 to 20 minutes, or until at least half of onions are browned and caramelized, stirring occasionally. Add garlic and 1 Tbs. oil. Cook 1 minute, or until garlic begins to brown. Add kale to pan, and cook 5 to 6 minutes, or until kale has turned bright green, stirring occasionally. Remove from heat, and season with salt and pepper, if desired.Meanwhile, roll out pizza dough as thinly as possible. Place on pizza stone or baking sheet sprinkled with flour. Bake 4 minutes to ensure crust gets crisp (pop any bubbles with fork).Drizzle crust with 2 Tbs. oil, sprinkle with sea salt (if using), and top with kale mixture. Sprinkle with Parmesan. Return pizza to oven, and bake 8 minutes more, or until cheese is golden, and crust is golden brown. Remove pizza from oven, drizzle with remaining 1 Tbs. oil, and slice into triangles.