Hey everyone, I had a question about if I could delete a part of a mesh without getting rid of any subdivision levels? I wanted to hide the hands of my mesh, delete and close holes then resculpt at the wrists to make some fists. Any help would be greatly appreciated 
You can delete parts of a mesh that has multiple subdivision levels only when you are on the lowest subdivision level.
but can I close those holes where the mesh has been deleted?
You can Freeze Subdivision Levels then use “Tool > Geometry > Modify Topology > Close Holes”, but as the topology of the closed hole will be triangulated, it might be less than ideal for sculpting and you would have to retopologize anyway. Another option, instead of closing the hole, would be to create separate geometry for the fist then use the CurveBridge brush to join the fist to the arm.
A fist is a closed hand…if you have low enough levels you can just shift the points with transpose, or move topo or move points.