An ultra-flush side-cutting pliers will give you one really clean end, and one that has a slight bur on it. Use the flat side toward the end you want flush. For a rivet, surprisingly, I often want to leave the non-flush side so I end up with a bit of a mound of metal that can be hammered down, but the good end of my wire has a nice flush end now.

These pliers should not be used on memory wire. Use carbide cutters for memory wire and other heavy or hard wires.