Potatoes – 2 pounds (1 kg) yellow (gold) potatoe – 3 tablespoons olive oil – 1 teaspoon organic lemon zest, optional – 1 teaspoon sea salt – 1 teaspoon sumac, and more for serving Tahini dipping sauce – 3 tablespoons (45 ml) tahini, more to taste – 1/4 cup (60 ml) water – 2 tablespoons (30 ml) lemon juice – 1/2 teaspoon garlic powder – 1/2 teaspoon sea salt, more to taste – 1/4 teaspoon ground cumin, more to taste For serving – 2 tablespoons chopped fresh parsley – 1 teaspoon sea salt – 1 sliced lemon