Show me the perfect treat

Positive clicker training requires the treat to be something of value to the trainee, something they really want! As a beginner I'm still on the big quest for the perfect treat, something my cats will go crazy for... It to be yummy, small, quick to eat, easy to handle. I'm forever looking for and trying out new ideas... If you have any ideas, let me know!


So far I have tried the following, with varying degrees of success (to be continued):
dried anchovies: Very dry, and too big for eating quickly. breaking in small pieces doesn't work: they are so dry and hard that chewing is a drag, and they end spat out 
chopped bits of edam cheese: Too chewy, it gets stuck on their teeth and takes ages to eat
cheese paste in a tube (for cats): Works well enough; I put blobs on my finger for them to lick off (this however prohibits using my finger as a neutral target) And I'm suspicious of what really is in this commercial paste... 
kibble (dry cat food): My favorite so far: clean, easy to handle, can keep it in my pocket at all times, reasonably affordable. The cats like it too! No wonder: kibble is addictive, and this is their only chance to get any in my house, as I feed them raw only. Which also makes me very guilty for using this at all, even if it's high quality no grain kibble.
chopped bits of bacon: Oily and messy, and not really that yummy (and too salty for cats, really...)
minced meat:   very yummy, and agrees with my raw feeding principles, but boy... this is wet and messy...
freeze-dried prawns: Clean, practical and yummy - but hideously expensive. A tub costs £2.99 and is gone after doing 2 training sessions with 4 cats...
freeze-dried tuna: slightly cheaper than the prawns, but comes in cubes that are too big to eat quickly (and crumble to dust when I try to break them up)
bonito flakes: These come recommended as 'kitty-crack'. I ordered some (the human thus cheaper version) from Japan Centre online and received two big bags of paper-thin shavings/ribbons of fish. Desirable they are, but I am at a complete loss as to how to get these brittle shavings into their mouths: the ribbons almost crumble to dust when I handle them, and all this fishy dust on the carpet it mightly distracting the kitties... Someone suggested to add water - this works better but is well messy!