i've heard of it for quite a few different frogs. you basically would build everything above the water as you would normally, but there's no substrate at all. just water. no, crickets will drown, your frogs will end up with nothing to eat. i would imagine those who keep their frogs this way use a bowl to feed and probably have an area for the bowl built into their background somehow.

you're probably best off doing a conventional tank, that's the safest route