Boil the potatoes in a pot of salted water until fork tender, about 15 minutes. Drain and set aside.
Heat a soup pot over medium heat. Add the olive oil, chili flakes, onions, green peppers and some sea salt. Saute for 10 minutes, and then add the brown sugar, some black pepper and the tomatoes. Let simmer for 20 minutes. Add the cooked potatoes and the zucchinis and cook until tender, 10 to 15 minutes.
Ladle the stew into a big bowl and serve with crusty bread.