In a large heavy skillet cook the onions in the oil over moderately low heat, stirring, until they are softened, add the garlic, the gingerroot, and the salt, and cook the mixture, stirring, for 2 minutes. Add the wine, 1/2 cup of the vinegar, and the peppers and cook the mixture over moderately high heat, stirring occasionally, until most of the liquid is evaporated. In a food processor combine the onion mixture with the dates and pulse the motor 3 or 4 times. Add the additional vinegar and pulse the motor 2 or 3 times, or until the mixture is combined well but still chunky. The relish keeps, covered and chilled, for 1 week. Serve the relish with grilled pork or chicken or with mild cheese and crackers.
