Weapon slots and controls can be swapped. Items and weapons can be used in either hand.

While you cannot natively swap the control sticks or buttons, you only need the sticks to move and (optionally) turn. It might take a little getting used to if you usually swap your control sticks.

Controls and equipment slots can be swapped. Items and weapons can be operated in either hand.

Controls are swappable and (as of version 0.13) equipment slots are completely customisable. You can hold any weapon or item in any hand.

While you can swap the control sticks, there does not appear to be a way to swap the left and right equipment/weapon slots. Though you can grab the equipment manually, this is cumbersome and awkward.

Your gun hand can be on the left, and controls, where not hand-agnostic, can be flipped.