Scoop the flesh from the avocados into a non-reactive bowl and discard any brown or discolored parts. Mash
the avocado using a fork.
Add the onion, half of the jalapenos, the tomatoes, cilantro and lime juice. Season with salt and stir to combine. Check piquancy and acidity, and add more jalapenos or lime juice if necessary.
Garnish with the queso fresco and serve the guacamole on a plate with the fresh totopos.