Unhooking

Like the Nike ad - "Just do it"
But close your depower strap first.

Unhook n keep ur kite low like below 45 n you will be fine

Yeah go for it!!

First try standing on the beach with your kite at 12. Pull the bar all the way in and hold it in. If the kite starts to fall backwards out of the sky, de-power a little bit and try again. Keep adjusting until your kite is happy to sit at 12 with the bar in for at least 10 secs. Note how much de-power you have.

Now try unhooking and just holding onto the kite (still on the beach) keeping it at 12 and pump the kite a bit and hook back in. Hook in and out a few times to get used to putting the loop back on to your spreader bar.

Get used to that, then power up and hit the water. Keep your kite powered and low and get lots of speed. When your ready, quickly de-power, bear down wind slightly (you need to be moving fast) and unhook. Ride for a bit then hook back in.

You'll want to do this a few times to get used to the pull of the kite and hooking back in. Make sure your safety is on properly so if you drop the bar your kite won't drag you down the beach.

Bob's your uncle

Worst advice EVER!

Start buy trimming the kite as said so it doesnt backstall, works best of you can trim while you ride. As the extra wind speed from your board speed give the kite less tendency to backstall.

Start by unhooking and riding down wind to get a feel for it. Then start trying to load and get some pop. Adding more speed until you have enough power to get some real pop.

The biggest thing is the practice the correct jumping technique hooked in. If you can on jump by moving the kite you are not ready to unhook yet. Practice 'loading and poping' hooked in without moving the kite for air. Board skills are much more important than kite skills for unhooked tricks.

It doesnt take much of a gust to send you up when unhooked. I couldnt tell you how many times iv been lofted by a gust while unhooked, some landed (badly) others ending in broken boards and injuries to myself.

Yes you can let go but it isnt exactly good for your kite to be dropped onto sand, standing in the water would be a much better idea, same concept at body dragging.
But if you dont have the board skills to figure out how to hook back in while riding you aren't ready to try unhooked tricks.

If you can stand on the beach and comfortably hold onto the kite unhooked there isnt enough power there to do anything unhooked anyway, you probably wont even be able to ride upwind.

If a gust "lofted you".
You let go of the bar, Simple as. It isn't a bad thing to do, I've seen people dump their kite multiple times on sand and water, over a period of time it is bad for the kite but who does it all the time when beginning.
If you have had a bad experience with unhooking go have a cry, you were obviously doing it in a area where your own stupidity endangered yourself.

Bottom line is Do it in a area that is safe, away from others, where there is minimal risk to yourself and others.

you can't properly trim your kite on the move.

this tuning advice given by yeehaa is actually pretty spot on, just stand on the edge of the beach / water and keep kite at 12, sheet in fully. you'll notice the kite either stays put (GOOD) or it will start back stalling (flyingbackwards in towards the power zone) if this starts happening sheet out straight away! keep pulling in a bee's dick of depower until you can keep it sheeted in without stalling.
don't unhook on the beach though this part is not advisable, just incase you f*k up and drop your sail on someone's head.

as mentioned by the others ride along at decent speed, put your kite at 45 and bear off towards your kite, unhook ride a bit, edge against the kite to get a feel for the extra accell you will get then hook back in by bearing towards the kite and pulling the bar in.
do it a few times to get a feel.

then like 14nce said, start by learning how to pop off the water without the use of the kite. keep it at 45 come in with speed keeping bar pulled in, bear off for a second then do a sharp agressive cut hard into the wind, this will make you feel like your harness is being loaded suddenly and with a lot of power, once you feel like you're at the apex of that power push off with your back leg an this will give you some pop. your legs will fly out behind you a tiny bit, get used to that feeling and the feeling of pulling them back under you for the landing. land fairly flat on the board and riding downwind slightly.

do these two steps and get pretty comfy with it before trying a unhooked trick. you will either find it easier to learn a backroll or a raley.

And dont put to much weight on ur back hand when u pop coz it will send u up like mary poppings try to send it down slightly if at all. ripped my kite in half after a raily went mary poppins on me