Seeing new colors and mixing senses, can it be done without prior experience?

I was just wondering if there were any non-synesthates here who experienced senses crossing over in dreams. It happens to me all the time but I have mild synesthesia even in waking life. Since I was young (and long before I knew anything about synesthesia) I was fascinated by the concept of martian colors. I thought that if aliens came to earth, they and the things they brought could come in all sorts of new colors, colors we'd never seen or dreamt of simply because they didn't exist on earth. Then later in life I learned about the electromagnetic spectrum and I dismissed the concept until I learned about synesthesia.

I read that blind-from-birth people didn't dream visually because they'd never seen and so their brains couldn't generate vision as we experience it. Same goes for black + white - visioned animals; they dream in black and white.

So it follows that people that don't have synesthesia wouldn't see the colors of smells or the shapes of numbers in dreams. For me, however, if I concentrate while dreaming I can perceive the dream world as a completely synesthetic mix of senses, something that I've never experienced in waking life except on a small scale. So, I'm unsure of whether I'm able to bridge some gap while dreaming that I'm not aware of while waking or whether the potential was always there. If anyone who doesn't normally experience these things could attempt it in a dream it would help my understanding of dream reality greatly.