Heat the oil in a heavy large pot over medium-high heat. Add the onion, 2-3 tablespoons harissa, (less if the harissa is very spicy, more if it's mild, less if you don't enjoy a spicy soup, more if you do; it's best to start with a smaller quantity and then add more to taste later, I started with 2 tablespoons of Mina Harissa, but added another 1 tablespoon before serving), tomato paste and 1½ teaspoons salt. Cook until the onion is translucent, stirring frequently, for about 5 minutes. Add the cumin and cinnamon and stir until they release their enticing aroma, about 30 seconds.
Add the chickpeas with their liquid (the liquid in canned beans is very nutritious and helps thicken the soup, it's quite salty in regular beans, so a good reason to choose low-sodium chickpeas), and 3½ cups water (to get every bit of goodness from the canned beans, I add the water to the bean cans and swirl, this also rinses out the cans before tossing them). Bring the soup to a boil. Stir in the squash and return the mixture to a boil. Reduce the heat and simmer the soup uncovered until the squash is almost cooked, for about 12 minutes.
Add the cabbage to the soup and simmer until both the cabbage and squash are soft but still hold their shapes about 3 minutes longer, adding more water if the soup needs more liquid.
Taste the soup and add more salt and/or harissa if desired. Ladle into bowls, sprinkle with cilantro and enjoy. (This soup can be made 2 days ahead and refrigerated. Bring to a simmer before serving, thinning with more water if desired. It is even better on the second and third days.)