For single SIM following code works:
TelephonyManager tm = (TelephonyManager)getSystemService(TELEPHONY_SERVICE);
String imei= tm.getDeviceId();
Yes Android currently not supported Dual Sim. But you can retrive all possible details by using Java reflection.
I research for fetching dual SIMs details and it works on bellowed devices
Samsung Galaxy Neo
Moto E
Micromax A52
Micromax Canvas
Linovo P780
HTC Dreem
Moto G
LG
HUAWEI Y520-U22
LG-P705
Sony ST26i
I successfully get dual SIM Detials from above models