To cut the spare ribs: Remove the silver skin from the ribs, then cut them into bite-sized pieces.
To prepare the spare ribs: Place the ribs in a large bowl and cover with the water and rice vinegar. Mix well and let soak for about 5 minutes. Drain the ribs, then pat them dry with paper towels. Use a fork to poke holes all over the ribs.
To make the black bean oil: Place the fermented black beans, ginger, and garlic in a heatproof bowl. Heat the cooking oil until it's smoking hot, then carefully pour it over the aromatics.
To marinate the ribs: Add the soy sauce, dark soy sauce, oyster sauce, and cornstarch to the prepared ribs. Mix until evenly coated. Pour the black bean oil over the ribs and mix again until everything is well combined. Let the ribs marinate for at least 10 minutes.
To steam the ribs: Arrange the ribs in a single layer on a heatproof plate. Bring the water in a large steamer to a boil over high heat. Place the plate in the steamer, cover, and steam for about 20 minutes, or until the ribs are fully cooked and tender.
To garnish and serve: Sprinkle the sliced mini sweet pepper and scallions over the ribs. Serve immediately.