I’m pretty sure I did this once before, but for the life of me I couldn’t figure out how to do it this time around. I had made a document in Publisher in booklet format (eg. pages 4 & 1 on one side, pages 2 & 3 on the other side of a single sheet of paper for a 4-page booklet) awhile back and needed it optimized for my tablet (only one page viewable at a time, not a 2-page per sheet spread as in booklet form). I searched and searched before I finally settled on this way to do it:
1) In Publisher, print document with a pdf printer (i.e. CutePDF) and choose Statement for paper size and Portrait for page orientation. Under 2-sided printing options, set it to Single-sided and print.
2) Open unconcatenized file in PDFScissors and choose separate odd and even pages.
Select regions for each odd and even page. Click File, Crop & Save or Ctrl+S to crop and safe as new file.
The margins might not be perfectly even all around, but they will be narrow enough to not take up too much screen real estate from your view of the book.
ETA:
I also tried it in Briss and liked the results even better as it told me the exact dimensions of each page (evens and odds) so I won’t have any discrepancies in page size in the final product.