Season the roast evenly with 1 1/2 tablespoons salt and both peppers, rubbing it into the roast. Place the roast bone-side down in a rack in a roasting pan. Roast for 30 minutes.
Lower the temperature to 350 degrees F. Toss the potatoes with the olive oil, rosemary and 1 1/2 teaspoons salt in a small bowl. Scatter the potatoes around the roast and continue to cook until a deep brown crust has formed around the outside of the roast and the internal temperature reads 120 degrees F, an additional 1 1/2 to 2 hours. Allow the meat to rest for 20 minutes before slicing.
For the Salmoriglio: Warm a small skillet over medium heat. Add the olive oil and garlic and cook slowly until the garlic is golden brown and fragrant, about 3 minutes. Allow to cool. Whisk together the lemon zest and juice, rosemary, thyme and salt in a medium bowl. Drizzle in the olive oil and garlic and allow to sit at room temp for 10 minutes. Serve alongside the rib roast.
If using with the Blistered Baby Pepper Salad, pour the salad over the roasted potatoes, toss with additional olive oil and serve with the roast.