I am also switching from M100 as we speak. I just asked a very simalar question and this was my response. (M100 lets you do it in the “viewer”, FCP will not it seems)
Look at the timeline. At the left of each track you will see buttons that disconnect or reconnect the audio (or by dragging them around you can send one channel to a different channel). You can do this with the mouse or by holding down F7 and hitting 0 in the number pad, and then F8 and hitting 0 in the number pad.
If these buttons show the audio is disconnected then you can drag you clip and only the video will go. No audio.
In the same place (the left of the timeline) you will see the little padlocks. if you click on this to lock the audio then when you drag your clip to the timeline or canvas you will only get video no audio.