You can just reformat during windows install if you're keeping the drive and theres nothing sensitive to get rid of.
Otherwise you'll need to get something to zero out the data, a format/repartition will leave raw data on there which could be recoverable - im sure this is still the case with SSD but I could be wrong, if it was magnetic HDD platter then you'd really want multiple passes of zeroing out to ensure the raw data is irretreivable.
PDWipe is pretty good. Of course I could have this theory all wrong given its an SSD there may be an easier way but being marginally paranoid I would always do at least one zero out when I want it properly "clean"