Preheat a grill pan over medium heat. Brush the sliced vegetables with 1/4 cup canola oil. Season with salt and pepper and place on the grill. Cook until they have slightly charred and softened slightly, about 3 minutes per side. Remove to a baking sheet.
In a large bowl, whisk together the garlic, Italian seasoning, vinegar, remaining 1/4 cup canola oil, and salt and pepper to taste. Drizzle half of the dressing over the grilled vegetables. Stir the chopped olives into the remaining dressing.
Cut the bread into 4 equal pieces and slice open. Spread the olive dressing evenly on 4 bottom pieces of the bread. Top with a single layer of each of the vegetables, reserving the remaining vegetables for Round 2 Recipe Ratatouille Pasta. Sprinkle the cheese over each and place the remaining 4 bread pieces on top. Place in a panini press and cook until well toasted, about 5 minutes. (Or place on a well-oiled grill pan and place a heavy hot cast-iron skillet or griddle on top of the sandwiches, and grill until the bread is well toasted, about 5 minutes per side.)