I know that the width difference might present problems later on, but if I understand correctly then it should be possible. The bike isn't meant to be used in high performance circumstances, just the city.
However, if I understand correctly, the tire would have a larger diameter than the rim. Is that likely to cause me much trouble?
tl;dr If I have a 32-630 tire and a 20-622 rim, can I make the combination work?