Well, there is the Cut Faces tool, but as Maya is not a solid-modeler the revealed objects will be hollow.
Maybe a more skilled modeler in the modeling threads can help you determine if I am wrong, and there is some ability to in essence "Cap" the hole
Select your poly object(s), then in the Polygons menu set choose:
Edit Mesh > Cut Faces Tool > Option box.
In the options for this tool, make sure the checkbox at the bottm for "Delete Cut Faces" is checked ON.
Leave everything else default.
Then click in any of your viewports and hold your mouse down while you position the line that appears to help you visualize your cut angle.
(This can be changed later if needed)
Then, to animate the slice over time:
Select your object(s), and in the channel box INPUT area click on the polyCut# node to expand its' attributes.
Key any of the following 3 attributes to animate your slice:
Cut Plane Center X, Y, or Z.
Also in the attributes are Cut Plane Rotate X, Y, and Z to better help you tweak the exact angle you would like for your cut.
NOTE that everything is animatable so you have TONS of control over the whole process
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS