Cut each avocado in half and remove the seed. Scoop out the avocado and add to a medium size bowl.
Mash the avocado with a fork leaving some bite size pieces.
Add the juice from a lime and mix together. Cut the tomatoes in half and remove the seeds. Chop the tomatoes and add them to the bowl.
To the bowl, add the red onion, cilantro, jalapeno and salt. Mix together.
Do a taste test and add more salt if needed.
Top with grated Parmesan cheese. Serve chilled or at room temperature.