Just code something outside of Gideros that goes through each sprite image, makes a mask, draws that mask slanted and transparent, then draws the normal image on top.
The image will be slightly taller and wider, you then measure by how much and add this offset into a table and save the image. Once done, save the table.
Now add all the images to a sprite sheet and use the offset table to add to the x,y of the when you draw it.
You could do the same in Lua I suppose within Gideros either using a rendertarget spritesheet.
I have loads of draw time in SinisterSoccer (football game), so I just render a mask that has a skew to it - if you have the frame rate then you could do the same?