The MOXF is a synthesizer, you can edit any of the Voices so they behave more as you like. You don’t mention any specific organ so we can’t give you a specific answer, but you can identify which Element is responsible for what you are describing as “Key click” and you can reduce it or turn it off. Then you can store your version in one of the User Bank locations.

A Voice can be made from as many as 8 Elements. Each Element contributes to the sound. There is no “Key Click” parameter to adjust, there is either a Waveform (the sound source within the Element) that is responsible for the Key Click, or perhaps you are referring to the “percussion”... either way you Control the sound by analyzing what each Element is doing.

Without deep editing (again depending on which specific organ Voice) you may discover that the original programmer may have placed control of that on a physical controller. Check the Control Set as well as what each Element’s Wave Name.