Mashing on Shabbos. Making Chumas And A general rule for What is allowed to me mashed?

Continuing the discussion from Mixing and mashing on Shabbos:

Can you mash chick peas( garbanzos) on Shabbos to make Humas. Is it soft enough( is that the criteria) that it would be considered like Avocado…
And in answering could you please state a general rule regarding what can be mashed into a smooth paste and what cannot

Anything that will not crumble may be mashed into paste.