I will be going to the Outer Banks of NC for some kayak surfing, but I will be bringing my muni. Any hints for riding on the sand? It is usually pretty firm along the edge near the water. Thanks.
You will get a ton of wheel spin in loose sand, and you need to pull up on the seat and pedal hard. If you go fast enough, you can stay above the sand better.
Mosquito repellent. Lots of it. And don’t miss Dajio’s Restaurant. Great place to relax in the evening with lots of good, fresh, local food.
Oh, you wanted unicycle advice 
That’s pretty much it. You won’t have much fun trying to ride on the dry sand. Stick to where it is firm, and don’t try any hops, quick turns or maneuvers. You’ll auger right into the sand before you know it.
If you had a Larry tire you could have a blast riding on soft, dry sand. But with a narrower Muni tire, such as the 3.0 duro, you could still ride on fairly dry sand if your psi wasn’t too high.
Yes, my experience with those super-wide (~4") tires is that they’ll roll easily through dry sand, loose gravel or just about anything you throw at them. But assuming you won’t be buying a special unicycle for this, the main piece of advice I can offer is to ride straight.
On dry sand, the wheel will dig downward with any amount of twisting motion. The straighter your line, the farther you will get. It’s a great way to learn how straight you actually ride.
The wet, hard sand is a lot easier, but can still be challenging depending on your tire width. Back before MUni, when unicycle tires were mostly 1.75", even the wet sand was quite a challenge to ride on!
A narrow tire like the 3.0 duro. I like it. I’ll have to use that the next time a b*ker ogles my tire. 
If you have an old worn out tire I would throw that on your unicycle assuming it is about the same width as your current tire, and run lower pressure than you are accustomed to.
It’s more about technique than equipment though. The best way to find out what works best is to experiment.
Rinse the hell out of your uni afterwards!
I might take my KH20 to the beach with the family for some messing about, shame I am still pants at trials as there are some massive boulders there to prevent coastal erosion. 
Wear a fashionable one-piece rather than a bikini. The wheel tosses sand up one’s back and, if wearing a bikini, a good portion of that ends up in the panties part in an uncomfortable location. Maestro8 told me this from his riding experiences.
Last week I was staying at Butlins (well known holiday camp in the UK) in Minehead. Took my new trials uni with a 19x2.5 tyre for transport in the resort and to have a play on, and one day went for a ride on the beach. On the firm sand next to the water’s edge it took me a few attempts to get going, but once going I didn’t UPD until I headed up the beach towards the softer sand after a couple of hundred metres of riding. It felt like I was working quite hard to stay in balance though. As mentioned the trick is not to try turning too much when riding - I was balancing with my arms a lot more than normal in order to keep straight, and my sloppy mounting technique (I usually make a big turn to balance after getting on) was clearly an issue, and probably something I should work on.
I didn’t even dream about trying hopping on the boulders - hopped up and down a few kerbs though, and managed a couple of hops off the ~2ft high “platform” where the baggage trolleys were stored. Also used the uni for transport to go shopping at the nearby supermarket - the advantage over a b*ke being that once my rucksack was full I was happy to carry more stuff in a carrier bag in my hand (though a full load made hopping tricky!)
I love riding on the beach, you can go for miles and scenic miles, even in ugly built-up places where there’s no good riding anywhere else.
I always ride when the tide is going out, makes it a lot easier to stay in the damp firm stuff. When the tide is coming in, the sand has spent half the day drying out, unless you are right down in the wave action.
Also, salt water = evil, try to keep it out of the bearings. You’ll probably still get rust on bolts and whatnot if you don’t rinse it right off.