Preparing for laying ceramic tile - clean up after removing vinyl tile
I have successfully used orange oil to soften the adhesive holding vinyl squares. I used it undiluted in just enough quantity to soften the adhesive. Then I scraped up the softened adhesive with a floor scraper frequently scraping off the floor scraper with a 3 or 4" putty knife into a trash can.

I then went over it again with more orange oil wiping with paper towels. Finally I used an electric floor cleaner and mopped. The concrete was still glazed and the tile installer used some kind of floor grinder to roughen the floor. I was not present for this; I was out of town. (The serious professional installation specifications for ceramic tile state that fresh concrete is not to be finished with a metal trowel prior to ceramic tile installation.)