There are 2 steps to sign your application:
1. Generate a keystore using JDK's keytool, here is an example:
keytool -genkey -alias youraliasname -keyalg RSA -validity 10000 -keystore yourkeystorename
After executer this line, you should type your keystore password, several personal informations, confimation and type another password for your alias.
2. Sign your application (.apk) with jarsigner, here is an example:
jarsigner -keystore yourkeystorepath apkpath youraliasname
Type your keystorepwd to start the signing process.
After these steps, you can install your application on the emulator, or on the device? (I didn't try)