Can I control the movements of bones without animation

Hi,
I am very new to using Unreal for game development. I was wondering if in Unreal would it be possible to import a rigged character with bones and no animation into Unreal and control all the movements of the bones just by using Unreal? For example if I use blender for rigging a hand with bones without animation can I control the movements of the bones such as making a fist and then change to another hand gesture.
Thanks Alex
Let me know if you need more clarification.

Hi! Do you mean something like this?