Very simply you fry the crawfish tail meat similar to how you would fry shrimp, but remember, the crawfish are already cooked. Given that all you want to do create a crust on them similar to a shrimp then take them out of the oil. Store bought crawfish will be another mater, you would probably want to add a very little liquid crab boil the let them soak in that a while before frying.
Here's how we did it.
Make an egg wash adding a little bit of seasoning (be careful, the crawfish from a boil are already seasoned and if you over do it they may come out too salty or too spicy).
We used a boxed fish fry, I assume you could use flour.
Heat the oil to around 365°F
Put them a little at a time in the hot oil and just let them turn a light
Keep the oil above 350°F so the browning process remains quick.
That's it.
Munch on them as a snack or make a po-boy with Hushpuppies on the side.
Enjoy!