Prepare the gribenes: Thoroughly pat the chicken skins dry with paper towels, then cut them into ½-inch pieces and season with salt.

Place the skin pieces in a large skillet over medium-low heat, cover, and cook for 10 minutes.

Uncover the skillet, increase heat to medium, and cook for another 15-20 minutes until golden, stirring occasionally. Avoid deep browning on the skins, or they will taste burnt. Using a wide metal strainer, strain the rendered fat (schmaltz) into a heatproof bowl and set aside. Keep the gribenes in the strainer to drain, or transfer them to a paper towel lined plate. Season with freshly ground black pepper to taste and set aside.

Meanwhile, prepare the mashed potatoes: Place the potatoes in a large pot and cover with water. Salt generously and bring to a boil over high heat. Cook for about 15-20 minutes, or until the potatoes are completely tender. Reserve 1 cup of the cooking liquid, then drain the potatoes.

While the potatoes are cooking, clean the chicken livers: Trim off any green spots, membranes, and stringy white connective tissue. Rinse briefly under cold water, then pat dry with paper towels. Keep refrigerated until ready to cook.

Return the potatoes to the pot and place over low heat. Using a potato masher, mash the potatoes. Add the olive oil, salt, and pepper (if using), continuing to mash while gradually adding the reserved cooking liquid until the mash reaches your desired consistency. Leave in the pot and set aside. 

Sear the chicken livers: Place a large skillet over high heat and add 2–3 tablespoons of the reserved schmaltz. Season the livers with salt and pepper, then sear them in batches, flipping halfway through, until cooked to your liking.

For plating, start with a mound of mashed potatoes, top with the seared chicken livers, and finish by sprinkling the gribenes on top.