Can the KenKen puzzle be solved using the same ideas as for Sudoku?
I don't think there's a simple way to express KenKen as an exact cover problem, although it's certainly possible since exact cover is NP-complete.

I think it would probably be easiest to express it as a SAT instance. Expressing Sudoku as a SAT instance is not hard, and the arithmetic constraints can just be expressed as the disjunction of all of the possible values which would satisfy the constraint (which you would then need to convert to CNF).