The senior boys found ragging (the junior students) were suspended from the college.
Is this sentence OK?

Ok, but the term ‘ragging’ is fairly archaic in the West.

What is the modern terminology for ‘ragging’?
‘The other kids were always ragging on me because I wasn’t good at sports.’
Is this sentence OK?

'ragging on’is incorrect.
The others were always ragging me…

In that context it is even more archaic as ‘ragging’ is generally a term limited to use in public schools, as in the original context.

For the ‘modern terminology’ consider the meaning:

picking on; teasing; making fun of, etc.