How to delete an app from adb without knowing it's package name?

try:

adb root

Then enter adb shell

adb shell 

Find out your apps package name:

pm list packages | grep "your app name/something related to your app name"

Then use:

adb uninstall 

OR

pm uninstall

Here is a nice tutorial about getting information (Name, Package name, icon, etc) about Installed Applications on your Android Device, emulator.

This helper util/class retrieves all installed apps with the application name, package name, version-number and code as well as the icons. The method getPackages() returns an ArrayList with all the apps.

class PInfo {
    private String appname = "";
    private String pname = "";
    private String versionName = "";
    private int versionCode = 0;
    private Drawable icon;

    private void prettyPrint() {
        Log.v(appname + "\t" + pname + "\t" + versionName + "\t" + versionCode);
    }
}

class PackageInfoUtil {
    public static ArrayList<PInfo> getPackages() {
        ArrayList<PInfo> apps = getInstalledApps(false); /* false = no system packages */
        final int max = apps.size();
        for (int i=0; i<max; i++) {
            apps.get(i).prettyPrint();
        }
        return apps;
    }

    public static ArrayList<PInfo> getInstalledApps(boolean getSysPackages) {
        ArrayList<PInfo> res = new ArrayList<PInfo>();        
        List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);

        for(int i=0;i<packs.size();i++) {
            PackageInfo p = packs.get(i);

            if ((!getSysPackages) && (p.versionName == null)) {
                continue ;
            }

            PInfo newInfo = new PInfo();
            newInfo.appname = p.applicationInfo.loadLabel(getPackageManager()).toString();
            newInfo.pname = p.packageName;
            newInfo.versionName = p.versionName;
            newInfo.versionCode = p.versionCode;
            newInfo.icon = p.applicationInfo.loadIcon(getPackageManager());
            res.add(newInfo);
        }

        return res; 
    }
} 

After determining the Application's Package name, just delete/uninstall the application using adb.