Stem the peppers and coarsely chop (include the seeds); place in a 1-pint shaker jar along with the salt, olive oil, and vinegar. Cover tight, shake well, then store at room termperature. The sauce will keep well for about a month. Shake the sauce every time you use it. Note: For mellower flavor, roast the peppers uncovered for 15 minutes at low oven heat (300 degrees F.), cool until easy to handle, then slip off the skins. Otherwise, prepare as directed.
Recipe courtesy of Jean Anderson's Food of Portugal