In a large bowl, toss the eggplant generously with olive oil and salt, to taste. Spread out on a baking sheet and roast until the eggplant is soft and mushy, about 15 to 20 minutes. Reserve.
Coat a wide deep pot with olive oil. Toss in the onion and crushed red pepper and season with salt, to taste. Cook over medium-high heat until the onions are soft and aromatic, about 8 to 10 minutes.
Add the fennel, celery and garlic and cook for another 5 to 6 minutes. Stir in the peppers and cook for another 5 to 6 minutes. Add the zucchini, season with salt, to taste, and cook until the zucchini and all the veggies are soft and aromatic and starting to come together as a stew, about 5 to 6 minutes. Toss in the eggplant, 1/2 cup of water and the tomato paste. Cook until the water has evaporated. Dissolve the sugar in the vinegar in a small bowl and add it to the mixture. Stir in the raisins, capers, pine nuts and mint. Cook for another 5 to 6 minutes.
Let cool and transfer the caponata to a serving bowl. Serve immediately or even better tomorrow or the next day.