Heat a wok over high heat until hot. Add 1 tablespoon oil. Swirl to coat. Add tofu. Stir-fry for 3 to 4 minutes or until golden. Transfer to a bowl. Cover with foil.
Reheat wok over high heat. Add 2 tablespoons oil. Swirl to coat. Add eggplant. Stir-fry for 6 to 7 minutes or until golden and tender. Add to tofu.
Heat remaining 2 teaspoons oil in wok. Add capsicum and onions. Stir-fry for 1 to 2 minutes or until softened. Return tofu and eggplant to wok with black bean garlic sauce. Stir-fry for 1 to 2 minutes or until heated through. Spoon into bowls. Top with extra onions. Serve with rice.