Roast the peppers whole over a grill or in your oven’s broiler until the skin is slightly charred. Place them in a paper bag or a pan with a lid, as the steam will help loosen the skin. When they’ve cooled enough to handle, peel the skins and remove the seeds. Sprinkle with olive oil, vinegar, garlic and salt to taste. Let marinate overnight and serve as a side to grilled meats.