you have to make a dmenu entry, edit the dmenu.cfg or theme.cfg (depends on your dmenu version) with notepad++ (not normal notepad!!), copy the vice entry and edit it, so the executable is xvic20.dge or xplus4.dge.
Dmenu has to know where the files are or it will go blackscreen.
Here are my entries, edit them, so the paths meet your Dingoo:
MenuItem VicePlus4
{
Icon = "/usr/local/emulators/FrodoDingoo/commodore.png"
Name = " Plus4"
Executable = "./xplus4.dge"
WorkDir = "/usr/local/emulators/vice"
}
MenuItem ViceVic20
{
Icon = "/usr/local/emulators/FrodoDingoo/commodore.png"
Name = " VIC20"
Executable = "./xvic.dge"
WorkDir = "/usr/local/emulators/vice"
}