Place the chopped onion, jalapeno, and garlic in a heavy-duty zip-top bag.

Using a rolling pin, gently smash the ingredients in the bag to release their flavorful juices.

Transfer the smashed aromatics to a medium mixing bowl.

Halve and pit the avocados, then scoop the flesh into the bowl with the aromatics.

Add the cilantro, lime juice, Tajin, and salt.

Mash gently with a fork or potato masher until you reach a creamy yet chunky consistency.