Well, I'm not the most knowledgeble when it comes to scaley/slimy things; but from what I've heard, you would be best off with a gecko(since you want to handle it).

Newts and salamanders have more sensitive skin. Since their skin is designed to allow water to flow more easily through it, it also allows any chemicals, bacteria, etc. to get through the skin. Even if you wash your hands, its still not reccomended to handle newts often at all.

I, personally, like geckos alot. It seems like the #1 suggested gecko is the Leopard Gecko. I've heard of them living in 10g tanks, but my friend's leopard is very happy in a 20 gallon long. Thats the only breed that I can think of off the top of my head that doesn't need atleast a 20g.

Good luck!