Makes 6 to 8 sandwiches, depending on the size of the ciabatta

1 large globe eggplant, ends trimmed, cut into 1/3″-thick rounds
Salt
4 bell peppers of assorted colors
1/2 cup olive oil
2 medium red onions
1 large zucchini, cut on the diagonal into 1/3″-thick slices
1 large yellow squash, cut on the diagonal into 1/3″-thick slices
Kosher salt and freshly ground black pepper
6 ounces soft, mild goat cheese, at room temperature
1 1/2 teaspoons minced garlic
2 tablespoons extra-virgin olive oil
3 tablespoons minced fresh basil
1 loaf ciabatta, cut into 1/2″-thick slices
Balsamic Vinaigrette (recipe follows)