Back in the day, for a while there was a tool that you used to secure the knife sections on the cutting bar of swathers and it would squish the end of a rivit much similiar to that. Stainless would be tougher forsure.
Can't tell by the pic what size they are...
If they're 1/4 inch you can buy a cheap rivet gun from Princess Auto that'll pull 1/4 inch.
If you were close by I'd lend you the one I have.