Hello,

Currently there is no way to do M.tech in part time. However many colleges do provide online course or distance course for  Masters degree.
So for you don't need to go college to attend classes. Only you need appear for the exams.
Other than this you can also pursue small online courses which is as similar to master degree courses. However they are more of a application based course. Some of college where you can find these online courses are MIT WEBSITE. or NPTEL website.