Place 2 ti leaves or banana leaves in a crisscross pattern on a flat work surface. Season the uku with salt. Place 1 fillet in the center of the leaves. Top the fish with one quarter of the ogo and a slice of the lop cheong. Fold over the ti leaves to form a package and secure with kitchen twine. Repeat for the remaining 3 packages.
Place the laulau packages in a steamer or vegetable basket set in a saucepan of lightly boiling water. Cover and steam for 8 to 10 minutes, or until cooked through.
To prepare the sauce, in a bowl, combine the ginger, scallions, and onion. Season with salt. Let sit for 3 minutes. In a saucepan over high heat, heat the peanut oil until just smoking. Carefully add to the bowl. Add the sesame oil, stock, and soy sauce and mix thoroughly.
To serve, place the packages on individual plates. Cut open at the table. Top the fish with the sauce.