Belgium-born Gambia Under-20 frontman Cham played 45 minutes of a closed doors match against Motherwell last Saturday.
The 20-year-old former KV Mechelen and Sint-Truiden VV youth scored two goals inside 24 minutes as Ton ran out 3-1 winners against the SPL outfit.
Moore, assistant manager Mark McNally, and development squad coach David Hopkin were all immediately impressed and the Ton boss moved to snap up the striker.
After briefly returning home to Belgium, Cham flew back into Scotland yesterday morning and put pen to paper after a final round of negotiations.
Speaking exclusively to the Tele, Moore said: "Kabba has signed a two-year deal with us. It's done and dusted and we're pleased to have been able to get him.
"He is confident he'll score us goals and he certainly looks the part. It's something a bit different; we've thought outside the box. It's a case of nothing ventured, nothing gained.
"We're not getting carried away but he's got all the attributes we were looking for. We've got high hopes for him and we think he can do a job for us in the First Division."
The Ton boss has four strikers in Cham, Archie Campbell, David McNeil, and Tony Wallace - who he sees playing up top this term - and is now satisfied with his striking options.
He added: "Do I see Kabba as my first-choice striker? No, because there won't be an automatic first choice striker next season.
"It's about who puts the ball in the back of the net.
"We've got high hopes for him, wee Archie, the young boy David McNeil and Tony Wallace. They'll be our four boys up top who we think will get us goals."