These are from proper musical notation and aren't specific to Chinese tab. Looking at the musical notes themselves always helps me work out what I'm meant to be doing with my playing - even if my sight-reading of normal sheet music isn't as up-to-scratch as my tab reading!
A tie between two different notes is a way of denoting legato, which can be played on guitar with hammer-ons and pull-offs. Legato is basically just trying to play a string of musical notes as fluidly as possible, as if there is no defined break between notes (as opposed to picking every note individually). A tie between two of the same note, however, denotes that the note should be held on for the duration of the notes. For example, two of the same quarter note with a tie between denotes that you should hold on the note for the same duration as a half-note.
The small note with a slash through it is telling you to play that very quickly before the main note. It is a type of ornamentation or embellishment called a grace note. Specifically, a small note with a slash through it shouldn't take up any space of the main note, whereas a small note without a slash through it should take up a small part of the duration of the main note. In other words - with a slash through the small note, the main note should fall on the beat and the slash note should be played early, but without the slash through the small note, the small note should be played on the beat. I believe that is a point of contention though...
