The flares I've triggered (well inland, away from prying eyes) weren't a problem, if you follow the instructions. Keep the flame downwind (and overboard!!!) and hold the flare at the bottom of the flare - all should be well without losing time looking for gloves. I do not recommend wearing leather-palmed sailing gloves in this case. If a spark does blow back, chances are it'll melt the synthetic material on the back of most sailing gloves, creating a chance of a significant burn (melted synthetic stays in place and continues to burn you). With the back of a bare hand, it'll probably just bounce off, like the sparks from a party sparkler.
S/V One With The Wind
'85 Baba 35
"You and I may agree, but we could both be wrong."