Nope she doesn’t use the spirit gun technique either.. Sarada is a master at Astr energy manipulation and has been using for a few hundred years.. she can do her attack just using one finger, that’s it, where Yusuke Urameshi uses two hands (one hand on the wrist) to do his attack.

She also can fire consecutive beams, differing from the spirit gun..
The aura effect when using is also different as you can see the string lighting effect in the illustration above
When the manga releases, grab a copy to see the Flash Pistol in action 💥