To mine skeincoins you need to use the internal miner built in qt-wallet. Currently there are no other miners because Skeincoin uses a new Proof of Work (POW) algorithm that is energy efficient and secure. The first round of hashing is done using Skein, the second using SHA256 (Skein-SHA2).
First you need to correctly setup the skeincoin.conf file:
Next steps: open the debug console and type setgenerate true -1 to start mining using all available CPU cores. You can check current difficulty by typing getmininginfo in the console.