If you are looking for pinhead crickets to the feed to the sals as the get much more older, just buy some adults at a petstore and raise your own crickets, it isn't too hard and it will provide a steady supply of crickets of various sizes for the salamanders as they grow into adults, be warned though, raising crickets will make a hellishly bad smell.
And again, the members are providing you with very reliable information for raising your young larvae, and it really isn't that hard to find micro-foods nor is it very costly to gather natural pond gunk (full of tasty little treats for the little guys).