Trim the zucchini, and cut it length-wise into thin strips about ⅛ inch thick.
Trim the eggplant, and cut it length-wise into thin strips about ⅛ inch thick.
Cut the sides off of each pepper, discarding the seeds.
Place all the vegetables on a large baking sheet, and drizzle over ⅓ cup of olive oil. Mix well to coat.
Grill the vegetables in batches until slightly charred on both sides. Alternatively, lay the vegetables (in batches) in one layer on a baking tray and broil for 4-5 minutes, then flip and broil for an additional 4-5 minutes. Transfer to a serving plate.
To a small bowl add the vinegar, garlic, mint and salt. Stir until the salt dissolves. Then whisk in the olive oil.
Pour the dressing over the grilled vegetables, and mix well to coat.