Just the tiniest darn cut....
 

I've got a nice vredstein fortezza tire that's new the side tread still has all the knobbies on it. I got a flat after riding over some gravel yesterday. Figured it was just a snakebite and changed tubes, rode home. Made it home but the tire was flat this morning again, so I took the tire off and there is a TINY (<1mm) cut, but it definitely goes through the tire, but only just. When I bend the tire I can see silver shining in it (must be the tread/puncture protection).

Do I S-Can the tire or is there a way to repair it?

Put some super-glue in it - the malleable kind. It'll be as if the cut was never there.

The super glue will work but you can also glue a regular tube patch to the inside of the tire casing as reinforcement too.

and how reliable are these methods? I intend to do many thousands of miles over the next few months.

I've never seen malleable super glue. Link?

I've used regular 'ol Super Glue on sliced tires with excellent results. I have a Vredestein Fortezza SE that's on my bike right now with 1,200 miles since I glued the slice (a deep and long one due to glass).

The trick is to completely deflate the tire before gluing. Clean the cut, if you can, with grain or rubbing alcohol, and let it dry. Then apply a thin layer of Super Glue and press the cut together hard for about 1-2 minutes. Then let it dry, preferably overnight.

If done properly, the glued hole will last a long time. However, it's wise to check the mend after every ride, especially if you run at the upper end of the pressure scale. And if you're at all in doubt, replace the tire.

I tend to stay away from using a tube patch because it adds a tiny lump to the tire, which is very evident at higher pressure.

There should not be anything shiny in there. I'll bet there's a little shard of glass or shiny mica rock still inside the casing. Use a needle and dig it out. The fact that your new tube went flat says that this is the case. Last I heard our bicycle tires do not use steel belting and cotton or kevlar doesn't shine back at you... :D

A 1 mm hole through your tire is nothing as long as there isn't anything inside that'll result in more flats. I've got tires I commute on regularly with 10 to 15 such holes that occured over the last 5 years right through the tire and they are fine. But I take the time to dig out the glass, wire or thorn remnant that caused the flat even if it means slightly stretching the hole in the tire to get to the problem causer.

how i do it exactly

Use pick then dig it out?

I guess something didn't translage well? Let's try again.

Use a large sewing needle or a sharpened spoke made into a long tapered needle and poke around in the hole until you feel something hard that scrapes against the needle. Use the needle or sharp spoke to lever it out.

Try to be as gentle as you can to avoid more damage to the tire but you need to find the piece of rock or glass that caused your two flats and remove it.

It's sort of like digging at a deep sliver in your hand. You want to do as little further damage as possible but it's GOT to come out.

Absolutely!! I had three flat tires in 45 minutes earlier this week because I didn't see anything in the tire and just replaced the tube, TWICE.

When I got home (having my wife come and get me in the car for the only time in 20+ years, btw) I pulled the tire off and VERY carefully inspected it from both the tread and casing side. Sure enough, there was a very small sliver of glass in the tire that was almost invisible. The point of a small pocket knife removed it and the bike has been trouble free since.

That did it I think. I must have ridden over some glass earlier in the day and rolling over that rock drove it home. At least i think it was glass. Otherwise there was a hard sharp brown shard of something on my shirt with no idea how it got there. I can't feel anything in there now and it took me two passes around the tire with my thumb rubbing it to find the hole again.

I'll try the superglue trick. Should I put any on the inside of the tire as well? The cut did come all the way through.

if you are concerned about it, you can apply a regular tube patch to the inside of the tire.

As someone mentioned that leaves a lump.

If it's only a couple of mm's long don't worry about it. As I mentioned I'm running tires on at least two of my bikes that have enough of these 1 and 2 mm holes right through the casing that the tire could qualify as a colander and it has not been any trouble at all even after a couple of years of riding on the same tires with the same holes.