I've had a couple pm's asking for the exercises I mentioned, so I thought I'd just post them here. They have helped me; maybe they'll help you.
1. Bend each finger as far back as you can without breaking anything. Hold it there a bit, then release.
2. Close both hands in fists as tight as you can. Then open them as wide as you can. Do this 10 times.
3. Grasp each finger with the opposite thumb and foreginger; shake each finger gently, and feel it loosen up, especially at the base knuckle. This sounds like it's too simple, but don't skip this one. It's very effective for me.
4. Hold the right hand with thumb facing away from you, palm facing to the right. Grasp the right thumb with the fingers of the left hand, and place the left thumb between the 2d and 3rd knuckles at the base of the fingers of the right hand. (It sounds complicated, but once you do it, you'll see what I mean.) Push with the left thumb while pulling with the left fingers, to rotate the right palm even farther to the right. Hold the stretch while you extend the arm fully, so that the right thumb points straight down. Do the opposite with the left hand.
5. Shake out both hands and arms, feeling them loosen up and relax.
I do these several times a day, when my hands feel stiff or numb; also before riding, and once or twice during the riding day.
Also, every day I pay attention to the hand positions that cause tingling, and I try to avoid those positions. I use a split keyboard--big difference. And I use a speaker-phone, to avoid holding the phone to my ear. I want to use my hands for important things, like playing guitar and riding motorcycles.