Step 1: Cut the zip tie tail off using whatever semi-appropriate tool is at hand.

Step 2: Remove nail clippers from your purse.

Step 3: Use them to trim the remaining tail. One single satisfying click is sufficient to leave an end that barely protrudes, is nicely-rounded, and which lacks sharp-and-pointy features.

Alternatively: Use the China-clone of the Xuron flush cutters that your 3D printer came with, or buy some (the real ones are made in Maine). Just cut it as close as you can.

Or for higher volumes and/or better repeatability, Panduit (and others) sell installation tools that tension zip ties and automatically cut them off rather exquisitely once a predetermined tension is reached by just squeezing a handle.