Place the red peppers and tomatoes into a blender or food processor and blend until smooth. Set aside.
Coat the bottom of a large pot with olive oil and place it over medium heat. When the oil is hot, add the onion and sauté until soft and translucent, about 5 minutes. Add the garlic and cook about 1 minute more, until very fragrant.
Add the red pepper-tomato mixture to the pot, along with the cauliflower, water, tomato paste, paprika, cumin, cayenne, and sugar. Give everything a stir to incorporate, then raise the heat and bring the mixture to a boil. Lower heat and allow to simmer until the sauce thickens up a bit and the cauliflower is tender, about 20 minutes, stirring occasionally. You can add more water to the pot if needed while the stew simmers. Make the polenta (instructions below) while the stew simmers.
Stir in the chickpeas and cook 1 to 2 minutes more, just until heated throughout. Remove from heat and stir in the salt. Taste test and add more to your liking, along with black pepper to taste.