Set a medium saucepan over medium heat; add the finely minced onion to the dry pan and cook, stirring often, until softened and most of its moisture evaporates, 6–8 minutes.
Add the niter kibbeh and cook, stirring, until the mixture is glossy and the onion is very tender, 2–3 minutes.
Stir in the berbere and cook until fragrant and brick red, about 1 minute.
Add the finely minced garlic and cook, stirring, 30–60 seconds.
In a bowl, whisk the chickpea flour with the water until completely smooth with no lumps.
Gradually pour the slurry into the saucepan while whisking; reduce the heat to low and simmer gently, stirring frequently to prevent sticking, until thick, creamy, and glossy, 15–20 minutes (it should hold a ribbon on the surface and bubble like slow lava).
Season with the kosher salt, taste, and adjust as needed; serve hot with injera or bread.