Destroying terrain

[Walrus]

I think that this is possible using engineer units (maybe only vehicles though) but I have never done it and am not sure how.
I assume you'd need to be facing, or on top of, the hex you wish to destroy (same as you would do for mine clearing) but then there is probably a key command to commence destruction. I imagine your unit would need to be unsuppressed (suppressed units would work slower, or not at all, same as mine clearing, or ammo resupply).

Have another look in the instructions or ask at the Shrapnel Steel Panthers forums.
That's where all the guys who play against the AI (mostly) hang out. One of them (or the designers) will know.