Use the scancel command to kill your jobs.

scancel -u chris

Will kill all jobs for user chris (you can only kill your own jobs).

scancel NNNNNNN

Kill a specific job. Get the job number from squeue, or from the output of job submission.

Note: It's scancel not skill. Skill is a command available on Linux but is not part of SLURM and will not kill your SLURM jobs.