You don’t have to sauté the vegetables, but I think it really brings out the flavors better. If not sautéing, simply mash them directly in the bowl with the black beans and other ingredients.
To get evenly shaped burgers, line the lid of a jar (I use a peanut butter jar lid) with wax paper or foil. Stuff the lid with the burger mixture, then flip it over onto the baking sheet and remove the wax paper.
Store in an airtight container or bag for up to 1 week. You can also freeze and reheat these.