Thank you, all of you, who contributed by answers or comments to the thinking that leads now to this answer. I listened to all of you, and it worked. I can't describe how tickled I am. Your suggestions opened my mind to thinking that this could still "work" even if it didn't quite go as I had hoped. As it turned out, the end product exceeded my hopes.
This is my soon-to-be-world-famous Dulce de Leche ice cream. Two nights ago I froze a batch with my new caramelized salt. It wasn't my intention to create a swirl-in, but once I had the candy, I had to try it that way.
Just before snapping the picture, I sprinkled some of the candy on top. Then I took a bite. HOLY COW!
The candy hits the tongue as just sweet. Then it morphs. In less than a second you start to get the bitter notes of dark caramel, then BAM it hits with salt. It ends salty and sweet, with the bitterness just a memory. By then, you've already got your next bite ready, as in, "What the hell just happened?" Paired with the very one-note sweetness of the Dulce de Leche, the multitudinous flavor bursts of this little crunch are phenomenal.
Are you reading into this that I'm a little excited right about now?
The candy that was swirled into the ice cream did NOT make the surrounding ice cream salty. It just swirled in, but kept its own character, albeit stickier and less (but still) crunchy. It's a great contrast to the creamy Dulce de Leche.
I discussed this small triumph in chat before posting this answer. Logophobe immediately jumped to using the "dust" (I'll show you that in a bit) to rim margarita glasses. The "margaritas" would be made with this. Oh hell yeah.
How about as a pork rub? Hell, HELL yeah!
The possibilities for this stuff are endless.
I hope by now you're intrigued enough that you want your own caramelized salt to play with.
I basically stuck with my original plan, but I didn't use Maldon; I used inexpensive large crystal (rock) sea salt, like you might put into a grinder.
First, I just made a dry caramel as per David Lebovitz using 1/2 cup (100g) of plain granulated sugar. I took his advice and brought the caramel to a darker point (closer to burnt) than I might have otherwise.
(Mr. Lebovitz' photos, not mine)
At just the very last possible second, I stirred in 100g of rock salt and poured that onto a greased sheet pan. After it cooled, it looked like this:
I broke off a tiny bit and tasted it. Too salty. I could barely discern any caramel at all. Hmmph. Well, I didn't expect this to go that easily.
What to do, what to do?
What if I break this up into chunks and do it all over again? That might work...
So I broke it up and put it into a heavy Ziploc. Then I alarmed my neighbor (he called in panic) by beating the crap out of it with the smooth side of a meat mallet.
Then I made the caramel again, this time I used 3/4 cup (150g) of sugar.
At the last possible second I stirred in my salty sugar chunks and poured the mix onto the same greased sheet pan. I was hoping that this time would maintain the clumpy appearance of the last. It didn't; it immediately homogenized into a fairly smooth mass.
At this point I didn't have great hopes, but I figured I'd see if I could make anything useful out of this. I called my neighbor to warn him, then I proceeded again to beat the crap out of it.
At this point I tasted it and kind of liked it, but the sizes of the pieces were all over the map. I didn't like that. I also didn't like the way it looked; the dust marred the glassy appearance of the larger shards.
So I grabbed three sieves of varying fineness and proceeded to work the candy through the holes. Anything that went through the fine sieve I called "fairy dust". By spending some time working out the "dust" I was left with larger, cleaner shards. I worked those through a pasta colander, then a big pasta colander.
The first time around, anything too big to make it through the the big holes of the big colander got put back in a Ziploc and beat up again. That gave me more "fairy dust" and more medium shards. The second time around, the shards that wouldn't go through were small enough that they might make a nice garnish - 2 or 3 pieces on top of the ice cream. So I kept them. It was a good call, they're fun.
Swirled into the ice cream, I used the dust and medium shards. The dust dissolves, but it stays to itself. It doesn't make the ice cream next to it salty. The medium shards maintain their integrity, they don't completely dissolve, they provide some crunch. The big chunks look awesome as a garnish and since they stay in the mouth long enough to savor, you can really pick up their complexity.
Pretty amazing stuff from 2 inexpensive ingredients.
I didn't get the encapsulation effect I was looking for, but in the end, I couldn't be happier with how this turned out.
Next time I'm going to try just doing it in one step using regular kosher salt. It might work, but I'm guessing that it won't be the same. We'll see.