Metrics and Kerning can be changed with the keyboard or by typing in the value.
In Edit View select the Text Tool.
Adjusting the spacing of the selected glyph:
With this ⌘+← / ⌘+→ you change the right side bearing
and with⌃+← / ⌃+→ the left side bearing
use ⇧ (shift) to move 10 units
Adjusting the kerning of the selected glyph:
⌘+⌥+← / ⌘+⌥+→ for the kerning with the letter to the right
⌃+⌥+← / ⌃+⌥+→ for the kerning with the letter to the left
use ⇧ (shift) to move 10 units
The Glyph inspector pane shows all necessary values.