Brush the sandwich toaster with a little sunflower oil, wiping off the excess with kitchen paper. Preheat the sandwich toaster to its highest setting.
Spread the two slices of bread with the hummus. On one slice, clover the hummus with the peppers, onion, and coriander. Place the second slice of bread on top (hummus side down). Carefully transfer the sandwich to the toaster, close the lid, and cook for 3 minutes until browned.