How do you defrost frozen chilli peppers without them going soggy? (I suppose this applies to other frozen fruit and vegetables with a high water content.)
I'm afraid this is impossible. It's the freezing, not the thawing, that causes this. Remember, water expands when freezing, so the freezing process breaks the cell walls, so when the pepper thaws, it has lost its crispness.
This doesn't matter if you're going to mince it finely or cook it, though! I freeze peppers regularly.