Put diced tomatoes and chopped onion in a large pot. Sprinkle with the pickling salt. Let stand overnight in fridge. Drain off as much juice as possible.

Add the cayenne pepper and vinegar, and cook for 45 minutes over medium heat.

Chop the green, red, yellow, and jalapeño peppers.

Add everything to the pot and cook for another 20 minutes. Continue cooking over medium heat, stirring occasionally.

Seal in canning jars.