Most shops, or nearly all near me only sell nuts at christmas time. I dont know about any asian food shops but I know one asian food shop sells coconuts where no other shops do because to them, they are 'out of season'. Brazil nuts might be a good nut to get into if they are ok for hams. The shells are very tough.
My hams wont even break into a monkey nut. Not even if I crack the shell myself a bit so they can smell the nuts.

Do not give Almond nuts to hamsters though. Almonds (Contains Cyanic Acid)