Optional: Spread diced onions on a baking sheet and season with a bit of pepper. Roast your onions in a preheated, 435 degree oven until the onions are tender and the cut surfaces sare golden brown (about 25-30 minutes). Roasting brings out unbeatable carmelized flavor!
Fill roaster with tomatoes (if not using diced, crush your hands or use an emersion blender as you add them to the roaster)
Add onions, bell peppers, jalapenos, garlic, vinegar, lime juice, sugar, salt and tomato paste. (Note: you may have to let the tomatoes cook down before adding the sugar, vinegar and tomato paste so that ingredients fit in the roaster).
Simmer 2 to 5 hours to desired thickness. Stir occassionally, scraping sides of the roaster to deter burning. Add/adjust salt, sugar, and peppers to taste. You can add tomato juice if the salsa becomes too thick.
Ladle hot salsa into clean, hot jars, leaving 1/2 inch headspace. Remove air bubbles with a debubbler with a debubbler.
Clean jar rims with distilled vinegar or water. Center canning lid on jar and adjust band to finger-tip tight.
Place a jar rack in a tall stock pot. Place filled jars on rack and add enough water to cover jars by 1 inch.
Adjust heat to medium-high, cover pan with lid and bring water to a rolling boil. Once a boil is reach, process pint jars for 15 minutes and quart jars for 20 minutes. Turn off heat and remve cover. Let jars cool for 5 minutes.
Remove jars from canner, do not retighten bands if loose. Cool for a minimum of 8 hours. Test seals. Label and store jars in a cool, dark place.