Cook pasta according to directions. Reserve cooking water to bind the sauce.
In a large pan, over medium heat, add oil and sauté shallots for 1-2 minutes until soft. Add capers, lemon juice, lemon zest and garlic. Sauté for another 1 minute. Cook down kale and zucchini ribbons until tender (~5 minutes) with a lid on the pan. If your cooking liquid has reduced significantly, add ½ cup of pasta water as you cook the vegetables.
Add the cooked pasta to the pan, season with salt, pepper and chili flakes and combine until the pasta is evenly coated. Add addition pasta water, if needed. You should have enough sauce to coat the pasta, not drown it.