At the north end of Arid Hills, just to the west is a camp with some bandits. Get rid of them. At the southwest end of the camp by the entrance, there are a series of cliffs which you can jump on. Go up here. You will be able to target Moe & Marley ( luring them within eyeshot of this location may be necessary) and fire while taking minimal or no damage. Some smaller Skags will still jump up at you, but they can be killed easily. Note: Watch for when they open their mouths; if you shoot them in their mouth it will deal significant damage.