If we want to run with the comparison of a cat's nails (which is a good one), it's not really like de-clawing them. It's more along the lines of trimming them back. We all know a ray's barb constantly grows. We aren't looking to cut out or fully remove the barb (like a de-claw for a cat). Some have tried that, and I don't know of anyone who has done it successfully.
Trimming is very straight forward, and it something I've had interns and entry level keepers doing. If you keep rays well, it is within the range of skills you can/could have.
Since we are techincally talking SW rays (and I should probably move this thread to that section), we have to look at what type of ray we are talking about. Benthic rays (lke yellow, cortez, Atlantic, Southern etc...) all have a barb located about midway down the tail - very similar to the FW ray counterparts. THey are very good with swinging the tail to use the barb. Pelagic rays (cownose, spotted eagles etc...) have a barb right at the base of the tail. They do not have control of the barb like a benthic ray. It's more like a spine that stays in place for them due to most predatory animals coming up from straight behind.
These are pictures of a cownose stingray. The barb is at the base of the tail. These animals were conditioned to lay (mostly) still after being scooped up in a large soft rubber net. We used one person to secure the animal, and one to trim the barb. Took about 10 seconds out of the water, and they were put back and swimming normally with no signs of stress what so ever. Yes, that is my hand. You can see the base of the previous trimmed barb still attached. There is no bleeding, infections, sores or anything negative to the animals health.
On a ray that has the barb mid tail, it's a little more involved. I like to pull them out into a flat container with just enough water to cover them, and have an airstone for increased disolved oxygen levels. I use a wet towel (with tank water) to lay over the back half of the ray and the base of the tail. Then secure the tail by hand, approaching it from over the body (you don't want to move your hand up the tail from the tip towards the barb - I know, but some people try anyway). With a firm grasp on the tail so it can't swing, slide the ctter (or whatever tool you are using) up under the barb and trim. Again, you don't want to force it too far up, just get it under where you can and trim the barb. What you are looking for at the end is a blunt stub. I know I have more pics somewhere, but I'm guessing they are on my laptop at home. I'll find some and post them later to show how this type goes. More or less, it's the same process. ONce you get used to it and the rays are adapted, it's something you can do by yourself. At first I suggest a two person team in a well lighted area.