Prepare the tomatoes: Wash and dry the tomatoes. Use a skewer to poke a hole through each of the tomatoes.
Add the spices to the jars: Add the garlic and peppercorns to the jar.
Add the tomatoes: Pack the tomatoes into the jar.
Make the pickling brine: Combine the vinegar, water, salt, and sugar (if using) in a small saucepan over high heat. Bring to a rolling boil, stirring to dissolve the salt and sugar. Pour the brine over the tomatoes, filling the jar to within 1/2 inch of the top. You might not use all the brine.
Remove air bubbles: Gently tap the jar against the counter a few times to remove all the air bubbles. Top off with more pickling brine if necessary.
Tighten the lid: Place the lid over the jar and screw on the ring until tight.
Cool and refrigerate: Let the jar cool to room temperature. Store the pickles in the refrigerator. The pickles will improve with flavor as they age — try to wait at least 48 hours before cracking them open.
Storage: These pickles are not canned and can be stored in the refrigerator for up to 2 months. If you process and can the jars, they can be stored at room temperature unopened.