I have an iPad 2 that no longer recognizes the SIM card tray, so I got the "no SIM card installed" message occasionally, and the "No SIM" message was always sitting in the upper left. This bothered me. In my case, I simply wanted the cellular radio turned off for good, to avoid seeing the "No SIM" messages, and maybe save some battery life.
Since the Cellular Data option is greyed out when there is no SIM, I could not get to the settings that allowed the radio to be turned off. Software updates and complete wipes and restores did not make this option available.
If your goal is only to turn off Cellular Data, and you don't have a SIM, nor Siri to help you, this is what worked for me:
1). Turn on Airplane Mode and wait at least 15 full seconds (really) to allow the wireless radios to truly shut down. This will buy you time in step #2.
2). Turn Airplane Mode back off, and IMMEDIATELY tap on the greyed out Cellular Data option. If you can get focus to this option during the split second before the iPad realizes there is still no SIM, you'll see all the Cellular Data options appear on the right, including its on/off switch, but all greyed out. Getting warmer.
3). Repeat step #1.
4). Turn Airplane Mode back off once again, and this time, quickly dismiss the "no SIM installed" message, and then you have a split second to tap on the Cellular Data on/off switch. Use two fingers. This can be frustrating, and may take quite a few attempts.
My environment for reference: Original iPad 2, iOS 9.0.2.
Paul