I think on some level you'll just get what you get with something hard like an almond. A really really sharp knife with a thin blade can help, but you can only do so much. My hand-cut ones are always a bit on the raggedy side.
When using a food processor, try smaller batches to leave bigger or more consistent pieces. You don't have to pulse as long to get everything broken up, so you get less that's ground to nothing. Do a small batch for a short chop, dump 'em out, do another.
As to how to do slivered or sliced almonds, I always figured that they started with blanched almonds (which are less crisp in my experience) or maybe even raw ones and then roasted them after cutting to crisp them up. You might experiment with blanched or unroasted almonds and see if you get a better result with a knife.
You might try welding gloves or fireplace gloves. (fireplace gloves tend to be longer, and might go up to your elbow).
They're typically made of suede, with an insulated lining. I use them instead of pot holders, but they also come in handy when I'm doing large amounts of grilling (once a year, for our departmental picnic, cooking for a couple hundred people).
The fireplace gloves also come in handy when camping, as you can reach in to move logs if you're quick about it. The only issue is that too long of exposure to hot, dry heat will cause them to harden up and lose their insulating properties. I have to get a new pair every few years or so because of the way I use them.
I also have some really heavy duty rubber gloves that I got more as a joke -- I'm not sure if they're for haz-mat purposes, or what, but they come in handy for when I have to deal with hot but wet things. I've also used them when dealing with cleaning out the fridge at work that had gotten pretty scary (it was near a conference room, and people using the conference room would leave stuff in there and forget about it). I've seen similar gloves, maybe not quite as thick, though, at a restaurant supply store near heavy rubber aprons for the people doing the washing up.
And, if those still don't fit your preferences, you can find silicone potholders ... they've got good grip, and you should be able to roll it into a cone around your piping bag.
Best Answer
I'm not an expert on candy-making, but it sounds to me as if you didn't heat the sugar sufficiently. The temperature that the sugar reaches will affect the texture when it cools:
I'd attempt to heat it back up to hard-crack state (300°F), and see if I could recover it.
Being that I don't have a candy thermometer, I'd probably try something stupid, like spread it out on a sheet pan (on a silicone mat) and bake it in a 325°F oven 'til it got close, then turn the temperature down to 300°F and just let it sit for a while.
Candymaking generally requires pretty specific temperatures ... I'm not sure that I'd trust a crockpot unless it was one of those digital controlled ones with a temperature probe. (but I suspect most of those are intended for meat, and may not be able to handle temperatures above 250°F)