Cut the eggplants in half lengthwise, then slice them into bite-sized pieces.
Finely chop the green onion, garlic, and ginger.
Heat cooking oil in a pan and grill the eggplants until golden brown on both sides.
Remove the grilled eggplants, add a bit more oil to the pan, and sauté the chopped onion, garlic, and ginger.
Add doubanjiang, soy sauce, sugar, vinegar, and water to make the sauce.
Stir-fry the eggplants and sauce together to finish.