Unless Apple made an iPad SSH client I don't know about, this sounds like you were just using a bad app. The first two that popped up when I just googled for "i

Unless Apple made an iPad SSH client I don't know about, this sounds like you were just using a bad app. The first two that popped up when I just googled for "ipad ssh client" clearly have control keys, as seen in their screenshots, and some other ones I've tried also have control keys.