Perhaps I'm just being a derp, but I can't find any way to multiply two vectors together.
The cross-product doesn't give me what I need.

Example:
Vector A = 1,0,0
Vector B = -5,0,6

I need a function that will output Vector C = -5,0,0

(-5 * 1 = -5)
(0 * 0  =  0)
(6 * 0  =  0)

Is there something I missed or is this currently not possible?

Vector Project will do what you want. Please refrain from posting help posts here next time.