Recumbent riders discuss performance 26" tires quite a bit.

The Shwalbe Kojak seems a popular choice for performance, but I have not tried it.
The Panaracer Pasella gives a very smooth ride.
Premo Comet is my favorite 26", just don't ride it in the rain.


A word of caution: when using relatively wide tires, don't inflate them to the maximum pressure on the side wall. Not only will you rattle out your fillings, you will loose traction and get more flats. There are many posts here on that topic.