Which tricep exercises do you think put the least amount of tension on the elbow
It's all about leverages, all of them will put tension on the elbow and if you have tendonitis, only do light, high rep while you recover.
If you're talking about injury prevention, I found close grip bench and diamond pushups to be pretty safe.
Also triceps pushdowns, not abruptly stopping at 90 degrees so there's less torque.