Narrower tires with a smooth or street tread take away most vibration
a bigger gear really helps too- the revs are so many less with a 36 as oppossed to a 44
I also like bars that are perpendicular- a safer, more relaxed grip is easier to get- I like alloy BMX with about an 8 inch rise- they're not the fastest, but easy on my bad back, and very lightweight
I have a front sprung shock- like a mountain bike, but on a cruiser- a bit difficult to find, but they're out there
between all those things, my hands never bother me