Yes, that's what you want. You can either add teeth by getting a larger chainring or subtract by getting a smaller cog. Cogs are generally easier and less expensive, so I would start by going that route. Your Fantom Cross shipped with a 16T cog, so you'll want to go smaller. 15T would be a step up, while a 14T would put you in the mid-seventies gear inch range that is popular for fixed riding (but, like most things, that's a very personal statement). Depending on how much gearing you're looking to gain, I would choose one of these options to start.