I'm not a practitioner of any M.A. Rob , and not to belabor a point ; but not necessarily would the icepick grip preclude 'any' slashing attack (IMO) providing the knife is held with the edge facing the opponent .
IIRC the kanjar is used with this type of grip .
Also IIRC most Puukos and Mora type knives are guardless as well .
Possibly your question about style of fighting with these weapons can be better answered by Yannis , or in a M.A. forum .