Siding repair
 

How to seal the bottom of siding to keep the keckos out ?

Try a search, use anole (the real name for the same lizards) gecko, lizard, etc., these was a thread with several good suggestions. I would avoid the one that said to use steel wool, as this will eventually rust, unless you find STAINLESS steel type.
We use the body wash plastic netting which we take apart and use the netting to fill small crevices. Works great and they last a long time, unless rain washes them out.

You could call Brian Terry Vinyl and ask for Wayne. He knows everything about vinyl siding and probably could help.