To begin, combine the vinegar, cinnamon sticks, peppercorns, mustard seeds, and chili peppers in a pot.
Bring the brine to a boil, reduce the heat, and simmer for 4 minutes.
Remove it from the heat and allow to cool.
Use several layers of cheesecloth to strain the solids from the brine.
Alternatively, you can put the solids into a muslin spice bag if you wish.
Discard the solids and keep the liquid.
This brine can be made the day before you can, simple refrigerate overnight. Or you can make it the day you are going to do the canning. (Day 2 of this recipe.)
Core and cut the tomatoes into 1/2 inch slices, cut the slices in half. For smaller, cherry sized tomatoes, simply remove the stems and cut them in half or quarters.
Place the tomatoes in a mixing bowl. Liberally sprinkle them with canning salt and stir them to coat.
Let the tomatoes sit overnight.
The next day, prepare your canning tools, canner, and supplies. Inspect and heat your pint canning jars.
Drain the liquid from the tomatoes with a colander. Thoroughly rinse and drain the tomatoes again.
Measure the quantity of your brine. You will have lost some liquid when simmering the spices. Add an equal amount of water, combining them in a large pot. Bring the brine up to a boil, then reduce the heat to keep it hot.
Peel, quarter, and slice an onion.
In each jar, add 1 tablespoon of the onion, 1 teaspoon kosher salt, 1 teaspoon minced garlic, and 1/8 teaspoon pickle crisp.
Add in your drained tomatoes to 1/4 inch of headspace.
Ladle in your brine.
Use a bubble wand to remove any air pockets.
Add additional brine to return the headspace to 1/4 inch if needed.
Wipe the jar rims with a damp cloth dipped in white vinegar.
Add the lid and ring. Place the jar in your canner.
Repeat the steps with all of the jars & tomatoes.
Process your jars for 15 minutes.
Allow the jar to cool in a draft-free location overnight. (12-24 hours.)
Remove the rings, test the seals on your lids, and label the jars.
Allow the jars to sit in the pantry for 3-4 weeks for the flavor to develop.
These green tomato pickles are best served chilled.