For Android, I suppose you could just run a Java bytecode obfuscator before converting the bytecode to Dalvik. There doesn't seem to be something comparable for iOS.
One simple solution is to set N-1 arrays to random data (hardcoded or generated at compile time) and set the last array to the real secret XOR random array #1 XOR random array #2 XOR ... XOR random array #N-1; this doesn't exactly stop a determined attacker, but it does stop "strings".
There's very little point obfuscating strings in iOS - since you can attach a debugger to the binary itself on jailbroken handsets (or using cycript) you can step through to the method(s) that use the secret keys and pull them out from there.
One simple solution is to set N-1 arrays to random data (hardcoded or generated at compile time) and set the last array to the real secret XOR random array #1 XOR random array #2 XOR ... XOR random array #N-1; this doesn't exactly stop a determined attacker, but it does stop "strings".