In my opinion, the easiest opening for white is the London System. You can play always the same moves no matter what black plays (almost ;) ) and nevertheless you have a totally satisfying position. Furthermore you play only logical moves, place your pieces on active squares and have a quite solid pawn structure so it is instructive, too.
As black mybe the Caro-Kann. It conveys a fundamental positional understanding and you get a feeling where your pieces are placed right. Moreover it is in some points quite similiar to the London System (active bishop outside of the pawns, similar pawn structure) so it makes sense to combine this two openings.
I am teaching new Chess players openings for White and Black, what openings should I teach for white and black? For White I was thinking of Queen's Gambit and Ruy Lopez, and for black French Defense and Slav. What are your thoughts on the easiest Chess opening?