According to the OED, 'winkle' is another soldier-sailor word, discussed in Fraser & Gibbons, Soldier & Sailor Words, 1925. It seems to me that, if the winkle was used as a food item, the word would be older than the WW1 date ascribed to it.

'Wankel', the rotary engine developed by the German inventor of that name.
Wankle not in OED Supplement of 1987.
'Wangle' as noted, is English 1820 in print. OED