Definitely a no go, as gross as bugs can be to handle, there are ways to indirectly scoop them up to feed your geckos.
Canned insects lack the smell/look and coloration that geckos react to, not to mention they're processed in who knows what and lack the nutritional value you gain in a live feeder that you can custom gutload to ensure that your gecko(s) are getting the proper nutrients it really needs as well as the hunting stimulation.
Good on ya though in managing to get your babes to eat one though, but I'd suggest sticking to their live food ^_^ pain in the butt it is, but worth taking the extra effort for a happy healthy gecko.
You can't gutload dead bugs. And who knows what they feed them in the cricket factory or if they were cooked and canned live or after being dead for days. If you have kept any crickets at all, you'll see that they die off a lot.
Plus, pickled cooked crickets are grosser to me than live bugs. My leopard geckos didn't care for them, either.
Actually, canned insects are fine as a way to add variety to your gecko's diet.
I would not personally rely on them as an exclusive food item, but they are awesome to use as an additive to your usual feeding routine. I often use the canned caterpillars, snails, and grasshoppers for my animals at home as well as in the stores. The few times large crickets or worms have been unavailable or difficult to get, it was very, very nice to be able to offer canned options instead.
While leopard geckos have been raised without any of these extra insects in their diet, and can subsist on a diet without them, I do not see the harm in increasing the variety of food items offered. ZooMed has a fantastic reputation and use all of their own canned insects in their personal zoo (they've got some awesome animals, check it out sometime), and judging by the health of their animals and my own, as well as the hundreds between all 4 of our stores, I can tell you the insects work well as an addition to the diet!
Most of mine, including my fat tail needed very little convincing. They snapped them right up. Those that didn't all it took was a little shake. I was planning on using them as a way to add variety to their diet, all I can get locally is crickets, supers, and waxworms. Now I can give them grasshoppers, caterpillers, and dragonfly larvae. It is also easier to dust, the canned bugs, I know they are getting their vitamins.
According to my herp vet there is no reason you can't feed processed versus live. She suggested using Flukers canned and freeze dried since our local mom and pop store get live feeders from them it will be the same insects only dead. She reminded me to dust them still with my vitamins and calcium powders.