Dip eggplant slices into egg, then coat with bread crumbs. Heat oil in 10-inch skillet over medium heat. Cook eggplant in oil 3 to 4 minutes, turning once, until golden brown and crisp.
Top each eggplant slice with onion and cheese. Cover and cook 1 to 2 minutes or until cheese is melted.
Spread pesto on bread. Top with cucumber, tomato and eggplant.