Apply gesture options currently are are hidden to deep in Animation dropdown menu>Apply Gesture Option to select which hands; in mocap editing almost in every case you need to replace hand/fingers animations, so I use it a lot and find it tedious to always reach to the menu to change hand to apply gesture from content browser, where it should be somewhere in main viewport - maybe in Timeline or in Edit Motion Layer window you could add 3 icons to select hands: left, right and both (please check screenshots);