。
I wonder when we'll be able to eat.
Literal
We [topic-は] when meal [subject-が] can-do [nominalizer-のか]-[wondering-な].
食事ができる ('can have a meal') uses the pattern [noun]ができる ('can do [noun]-suru verb'). The のかな ending combines のか (emphatic question) with な (wondering), producing '(I wonder) when...?'. This かな-style ending is the standard way to express 'I wonder.'