“Hi, is there a way I can convert my leopard frog tadpole to eat freeze dried crickets or prepared crickets when it metamorphosizes into an adult frog? What about wiggling a freeze dried cricket with tweezers in front of its snout?.”
You can try it. Frogs rely heavily on movement to trigger a feeding response. In fact, they have difficult seeing at all if the thing they are looking at is not moving. Some amphibians also rely heavily on their sense of smell, especially newts and salamanders, and for these species freeze dried or prepared diets can often be used instead of live foods.
For your leopard frog though I would recommend starting with live insects. As it grows try using freeze dried crickets and other foods by dangling them in front of the frog, perhaps with tweezers as you suggest. If you can get the frog accustomed to eating this way it is possible you might be able to switch it to prepared diets, though I don’t know how these may different nutritionally to live foods.
Bullfrogs in commercial farming operations are fed entirely prepared diets, and so I suspect it could be possible with leopard frogs as well.
Importantly though, if the frog shows no interest in the freeze dried crickets (and most likely it won’t have any interest at all) then go back to live foods. Leopard frogs are especially jumpy and nervous captive animals so my guess is that using freeze dried insects will not work.