Heat olive oil in a Dutch oven or soup pot over medium-high heat. Add the onions and a pinch of salt and let them sweat down until soft and translucent, about 5 minutes. Add garlic and sauté for another minute, until the garlic is fragrant. Move the onion and garlic mixture to 1 side of the pan and drop the tomato paste, paprika, cumin, and red pepper in the other side to toast for a minute. When you start smelling the toasted spices and the tomato paste has darkened slightly, stir them into the onion mixture. Add the sweet potato with a pinch of salt, the chickpeas, and chorizo to the pot. Stir to combine.Pour in enough stock to cover the sweet potatoes, chickpeas, and chorizo by about an inch. Bring to a boil, then reduce to a simmer. Simmer, partially covered, until the potatoes are nearly tender, 8-10 minutes. Add the kale, simmer for 5 minutes, then add the spinach and simmer until tender, about 2 minutes. Taste. Season, if needed, with salt and pepper.