At that size, the newts will happily take white worm. White worms are easy to culture - just keep them in damp potting soil (e.g. and ice cream tub full) and feed them on bread, reddybrek or fish food and they will not only stay alive but reproduce to the point where you will have too many to deal with! Once you have a culture going, you can add whiteworms to terrestrial tanks, where they will breed and provide food for newts to graze on outside of feeding time.
Adult (i.e. non-maggot) fruitflies only live a short time. To keep a supply, you will need to breed them. Take flies from your original shop-bought culture and put them in plastic pint glasses with new medium and a piece of kitchen roll or muslin secured over the top with a rubber band. Keep them warmish (23-25C is ideal) and they will reproduce. The substrate will become full of maggots, which will pupate and hatch into a new batch of flies. Use some of these and use the rest to propagate new cultures. Occasionally cultures may crash due to mould or mites, but you can then start up again with a new shop-bought culture. Try to source your original culture from a good source to avoid it being teeming with mites.
You can buy 'just-add-water' medium online from various sources, but a cheaper alternative is to make your own. I use Alan Cann's recipe:
Drosophila
with success.
When tong feeding, try to do it in the evening with reduced lighting to avoid scaring them. Try gently touching the food on the front of the mouth - this often elicits a feeding snap. If they are very shy, they may run away if you rub food directly on the mouth, so if this happens, try gently wiggling the food (just a mm or two side-to-side) on the ground in front of them.
An alternative to rearing them terrestrially is to force them back into the water. There are lots of older posts in this forum about rearing Cynops pyrrhogaster aquatically; here is one to get you started
http://www.caudata.org/forum/f1173-...423-raising-c-pyrrhogaster-fully-aquatic.html . Essentially, move the animals to shallow water stuffed with plants, so that the newts can easily rest with their heads above water, but never get completely out of the wet. After a few days of glass climbing (make sure you have a very secure lid and keep putting the newts back in the water if you find them on the glass), they will usually take to the water. Once in the water, they are much easier to feed and can be weaned onto frozen foods.
Good luck with them!
C