Resources on Cryptographic Applications of Expander Graphs I want to read papers on cryptography like 
How to Recycle Random Bits
or Security Preserving Ampliﬁcation of Hardness. They use random walks on expander graphs.

I need a short introduction to the subject of expander graphs and random walks on them. I prefer one that has cryptography in mind.

PS: In another post, Dai Le introduced the paper Expander graphs and their applications, S. Hoory, N. Linial, and A. Wigderson as an excellent paper on expander graphs. Unfortunately, it is too long (123 pages) to be useful for me.
I suggest you look at a survey by Oded Goldreich, called A computational perspective on sampling. In that survey he presents some basic facts on expanders (along with pointers to more extensive material). These facts seem to be sufficient to at least understand the "Security Preserving Amplification of Hardness" paper. In particular, in appendix A he surveys random walks on expanders, and in C.4 he presents the expander hitter, which is what is essentially done in that paper.