You should be able to build and test for the iOS simulator without a team ID. Install Xcode, then run either:
openfl test ios -simulator
or
openfl update ios -xcode
(the latter command generates the Xcode project template, then opens Xcode for you to manually run, or the first command tries to do it all automatically for you, but installing and running on the simulator is sometimes flaky)
For a device, you will need a team ID. I recommend opening ~/.lime/config.xml (which includes defaults added to every Lime project on your system) and adding <config:ios team-id="" /> with your team ID. You Apple develoepr team ID is viewable from the Apple Developer site, under your Profile, if I remember correctly. Doing this once means you won’t have to do it for each individual project, though that’s another you could do it 
Then you can run a similar command to build and run, or do it from Xcode if you prefer
openfl test ios
openfl update ios -xcode