Generate a minesweeper board which doesn't need guessing

The implementation of Minesweeper in Simon Tatham's Portable Puzzle Collection is guessing-free. (It's also MIT licensed, so you're free to copy his implementation if you so desire.)

It's well-known solving minesweeper is NP-complete.

This is true but perhaps not as relevant as you think. The proposed algorithm is something like "repeatedly generate random boards until the computer can solve one". NP-hardness is a property of the worst case, but here we're really interested in the average-case hardness. If an unusually hard board is generated, we can time out the solver and restart with a new board.

Also, even if there were an oracle to distinguish good boards from bad, would you really want the user to have to solve a hard problem in order to avoid guessing? A less talented computer solver might bias the choice toward fairer boards.