Skim coating floor for vinyl flooring in kitchen

[Benjamin Mueller]

Just took up some commercial carpet that was in the kitchen(yes the kitchen) of a rental I just got and it was glued down to the concrete.  There was also glue all over the floor from old floor tiles from a long time ago I assume from when the house was built. Do I need to remove the glue or can I skim coat right over the glue or is that a bad idea???