Process vegetables and herbs until fine in food processor.
Add liquids while machine is running; puree.
Add seasonings to taste; blend.
Place in airtight container.
Cover and rest overnight (or at least 2 hours) in refrigerator.
Bring to room temperature before serving.
An authentic Argentinean method: Boil the water, vinegar and salt together. Pour the mixture over the rest of the ingredients; then add oil. This slightly cooks the garlic and mellows the flavor; it also shortens the resting time.
You may also skip the blending and simply whisk the ingredients together, if you prefer a chunkier salsa. (Not recommended if using as a marinade.)
Red wine vinegar is traditional; but I prefer to use the balsamic / rice wine vinegar mix above.