Next, make the stew. Place olive oil in a large, heavy pot (like a Dutch oven) over medium heat. Once it’s warm, add onion, garlic, bell peppers, tomato paste, oregano and a large pinch of salt. Cook, stirring now and then, until vegetables begin to soften, about 5 minutes. Stir in zucchini, chickpeas, water and another large pinch of salt. Turn heat to high, and when that little bit of water begins to boil, turn heat to medium-low, cover the pot, and cook, uncovering it every so often to stir, until zucchini is very soft and mixture is stewy, about 25 minutes. Turn off heat, stir in vinegar and season mixture to taste with salt.