To prepare the eggplants, in a bowl, dissolve the salt and rice vinegar in water. Add the eggplants and place a plate on top to keep them submerged. Soak for about 10 minutes, then drain, rinse, and gently squeeze out excess moisture. Toss the eggplants with cornstarch until evenly coated.
To make the sauce, in a bowl, combine the soy sauce, dark soy sauce, oyster sauce, sugar, and water. In another small bowl mix the cornstarch and water to form a slurry.
To fry the eggplants, in a pot over high heat, heat the cooking oil to 350°F (177°C). Fry the eggplants in batches for about 1 minute until tender, then remove and drain on paper towels.
To stir-fry and braise, in a wok over high heat, add the cooking oil. Stir-fry the hot pepper and garlic for about 30 seconds until fragrant. Pour in the prepared sauce and bring it to a simmer. Stir in the slurry and cook until the sauce thickens. Add the eggplants and toss gently until evenly coated.
To serve, transfer the eggplants to a serving dish or clay pot and garnish with the scallions. Serve immediately with steamed rice.