Start by washing all fresh produce thoroughly under running water to remove any dirt or pesticides.

Peel and chop the tomatoes, ensuring to remove the cores. You can blanch them in boiling water for 30 seconds to make peeling easier.

Finely chop the onions, green bell pepper, and red bell pepper. Mince the garlic and chop the cilantro.

In a large mixing bowl, combine the chopped tomatoes, onions, bell peppers, garlic, cilantro, lime juice, salt, cumin, black pepper, and red pepper flakes (if using). Stir well to combine all ingredients evenly.

Transfer the salsa mixture to a large pot and add the white vinegar. Bring the mixture to a boil over medium-high heat, stirring occasionally to prevent sticking.

Once boiling, reduce the heat to medium-low and let it simmer for about 20 minutes. This allows the flavors to meld and the salsa to thicken slightly.

Taste the salsa and adjust seasoning if necessary, adding more salt or lime juice to taste.

While the salsa is simmering, prepare your canning jars by washing them in hot, soapy water and rinsing well. Place them in a water bath canner to sterilize.

Once the salsa is ready, carefully ladle the hot salsa into the sterilized jars, leaving about 1/2 inch of headspace at the top.

Wipe the rims of the jars with a clean cloth to remove any residue. Place the sterilized lids on top and screw on the metal bands until fingertip-tight.

Process the jars in a boiling water bath for 15 minutes to ensure they are sealed properly. Adjust the time based on your altitude if necessary.

After processing, remove the jars from the water bath and let them cool on a clean towel or cooling rack. You should hear a popping sound as the jars seal.