I have both the meat grinder
with the fruit/veggie strainer
and the veggie chopper
and I don't think either of those would work. The grinder and strainer don't really cut, just force the food out of various sized holes. I think the peanuts are too hard to be ground in the machine and would jam it. If you didn't jam it, I still think the holes on the smaller disk of the grinder are too big to do more than create chopped peanuts. The slicer is too big to deal with the peanuts, they'd fall through I think.
I think a food processor is a better bet.
ETA from the KA food grinder manual
|Note: Very hard, dense foods such as totally dried homemade bread should not be ground in the Food Grinder.
If hard bread won't work I think peanuts are out.