Is it dangerous to ride with a slight leak in one fork?
How will this effect that handling of the bike and is it hard to put a new o-ring in, is there a lot of steps to it or special equiptment?
IMO, not inherently dangerous per se, however riding with anything mechanical amiss is unwise. Best to get them rebuilt asap. If they are leaking, chances are thgey need an oil change anyway. I just priced this job for my wife's 750, about $160 for a complete rebuild for both both forks (parts only). I am hoping I can find an inexpensive pair of forks on ebay or craigslist and rebuild them and then just swap....minimize downtime.