It has been done
Techically ipl isn't really a laser
but it is similar in that both treat veins by applying heat to them. Ipl has certainly been used for treating red spider veins
on the legs but there are other methods of treatment that are more common these days, including rf thermocoaulation, laser, and sclerotherapy
Most of the time, when it comes to leg veins, vein experts will tell you that sclero is best.