I'm about to look for piRNAs in some miRNAseq data. What are the most well established programs or pipelines for detecting piRNAs in human small RNA seq data? 
I would not say there is one that stands out, but there are a couple which I would recommend:

- https://github.com/bowhan/piPipes
- https://www.smallrnagroup.uni-mainz.de/software.html 