This is from the back of the Morton's Canning and Pickling Salt box. I wouldn't generally post a canning recipe, but I personally think that Morton is a "trusted source". I have not tried this yet, but I had a request for this recipe.
Prepare canner, jars, and lids, following manufacturer's instructions. To make Pickling Liquid place vinegar, water, sugar, Morton® Canning & Pickling Salt, lime juice and black peppercorns in a sauce pan. Bring to a boil. Reduce heat to medium and continue to boil until liquid is reduced by one-fourth. Remove from heat and strain mixture into a heat proof container.
Combine 2 cups Pickling Liquid and remaining ingredients in a large sauce pan. Bring to a rolling boil, continuing to boil until onions are softened. Remove from heat. Ladle salsa into hot sterilized pint jars, leaving 1/2" headspace. Remove air bubbles using a non-metal spatula. Wipe rims of jars. Close jars as manufacturer directs. Process in a boiling water bath for 15 minutes. Remove jars and cool, undisturbed. Check lids for proper seal after 24 hours.
NOTE: Processing time above is for under 1000 feet. For altitudes 1000-6000 feet, process 20 minutes; above 6000 feet, process for 25 minutes.