There are, but they're irrelevant. At a reasonable rate of pedal rotation an MTB will top at about 35mph - if you have that much leg strength and don't mind arriving wherever you are going soaked in sweat.

Other than pedaling harder there are two ways to make a bike move faster on the flat (assuming your suspension forks have lockouts) -

1. Reduce air resistance. This typically means a low position that's less comfortable and less suited for keeping an eye on traffic.

2. Reduce rolling resistance by using faster tyres. Contrary to what most people think this doesn't mean thinner tyres but tyres made from better rubber compound. Marathon Supremes are a good choice for speed, grip, longevity and puncture resistance.

The Kona Smoke is probably a good choice for the type of riding you are doing, but - as long as those suspension forks on your current bike lock - I don't think it will make a noticeable difference in commuting time for you.

Oh - if the forks don't lock, then see if you can pick up replacement rigid (ie non suspension) forks cheaply at an LBS or on ebay. You should be able to fit them yourself, but if not a local mechanic shouldn't charge much.