It doesn’t look like it comes directly out of his palms but more like he’s able to materialize them out of nothing. So it also doesn’t look like he grips them either as they don’t have hilts. Just doing a quick search they’re described as beams of energy so I guess similar concept to lightsabers in that sense?
His KH III render gives a little bit more of a clearer look at how he wields them so I’ll link it below.
Also PS I think your illustration of Xemnas is pretty rad.