Cut the avocados in half, remove the pit and scoop the flesh from each half into a larger bowl. With an old-fashioned potato masher, a large fork or the back of a large spoon, coarsely mash the avocado.
Scoop the onion into a strainer, rinse under cold water, shake off the excess and then add to the avocado, along with the habanero.
Finely grate the zest from the citrus: you need about 1 1/2 teaspoons grated lime zest and about 1/2 teaspoon grated orange zest. Add them to the bowl, then juice both fruits and add 2 tablespoons lime juice and 1 tablespoon orange juice to the bowl.