Is it possible to type a hair space (u200a) and a thin space (u2009) in Ubuntu without entering the Unicode code? Something with the Compose key?
Got it! Keyboard preferences > Layouts > Options... > Using space key to input non-breakable space character > Non-breakable space at third level, thin non-breakable space at fourth level.
(The fourth level is called the same way as the third plus Shift. To set the 3rd level switch, go to Keyboard preferences > Layouts > Options... > Key to chose 3rd level.)