Hi!
I have some background in creating mobile websites, mostly optimising WordPress themes for mobiles, but OpenCart shouldn't be a problem.
I'm new to freelancing and I don't have any completed projects on this website, so I'm currently very flexible in the pricing. I'll be glad to have a look at your projects code and make the corrections to my offer if needed.
If you have any questions from your side, feel free to ask.
Hope to hear from you back soon.
Best regards.
Eduards.