Slice the avocados all the way around from top to bottom, and twist the halves to separate them. Carefully tap the pit with a sharp knife, twist and it will come right out. Scoop the avocado flesh into a large bowl. Add some of the lime juice as you prepare the avocados to prevent the flesh from browning.
Add the onions, chiles and olive oil to the bowl. Use a fork or a potato masher to mash the mixture, leaving some chunks of avocado for texture. Season with salt and add as much of the remaining lime juice as you like.