Wash all fresh vegetables thoroughly.
Dice the ripe tomatoes and place them in a mixing bowl.
Finely chop the red onion and add it to the tomatoes.
Seed and dice the jalapeños, adjusting the number based on your spice preference.
Add the diced jalapeños to the mixing bowl.
Chop the fresh cilantro and stir it into the mixture.
Squeeze fresh lime juice over the ingredients.
Add salt to taste and optional cumin for extra flavor.
If using, gently fold in diced avocado for creaminess.
Mix all ingredients until well combined and serve immediately.