Eggplant-and-Bulgur-Stuffed Vegetables

8 small round tomato es (about 2 1/2 inches in diameter; 2 1/2 lb total)

1 

3/4 teaspoons salt

4 small zucchini (1 1/2 lb), halved lengthwise

1 large onion , chopped (2 cups)

6 tablespoons extra-virgin olive oil plus additional for brushing vegetables

2/3 cup medium bulgur

1/2 teaspoon sugar

1/2 teaspoon ground allspice

3/4 teaspoon black pepper

1/3 cup dried currant s

4 small (not baby) yellow or orange bell peppers with stems (2 lb total), halved lengthwise through stem, then ribs and seeds discarded

1/4 cup chopped fresh flat-leaf parsley

Special equipment: a well-seasoned 12-inch cast-iron skillet