You could do a balsamic or red wine vinegar dressing. As long as it wasn't creamy or contained cheese (parmesan is common in bottled dressings) it would be fine.
My favourite dressing is:
1/4 cup red wine vinegar
1/4 cup olive oil
2 tbsp miced red onion
1 tbsp dijon mustard
Dash of salt
Fresh black pepper
Put it all in a glass jar and mix it like crazy for a minute
As for a main course..what about some kind of pasta dish? Or a vegan chilli?