Slice the eggplant in half vertically. Slash the flesh side with a few shallow cuts and prick the skin a few times with a fork. Brush with oil and season the flesh with a little salt and pepper.
Place eggplant, flesh-side down, in a lidded skillet. Add the water and put over high heat. Cook for 10 minutes or until the water disappears (watch carefully). Once the water has evaporated, add 1 tablespoon of oil to the pan along with the white parts of the green onions and the chili pepper. Add the teriyaki sauce, shake the pan to distribute the sauce, cover the pan, and cook for 2 minutes. Flip the eggplant over every 2 minutes to coat it with the sauce, cooking for another 10 minutes or until the eggplant is tender.
Top with the reserved green parts of the green onions and the peanuts.