I'm looking for delicious and unique!
Potato Champion!!! They're located inside of a little food stand/truck shanty on SE Hawthorne and their poutine is absolutely divine. They also serve really good Belgian fries with a variety of tasty, tasty sauces. You can check out their menu here.
I went there one night before dinner and didn't want to try too much because I didn't want to spoil my appetite, but everything else that people were ordering from the other food stands looked so good, too! What I liked about it was that there was a huge vinyl tent in the middle of the whole place. It happened to be cold and sprinkling that day, so I was really grateful for that!
Another good spot is Prost! on N. Mississippi. It's a German pub and though they have food, there's another food stand/truck shanty connected to it and the pub allows you to enjoy their drinks while you eat food from the food stands.
Enjoy Portland! I love it there :)
If you like to test yourself, try
Brunch Box. They have a dozen differeent types of hamburgers and are located right in the middle of one of the largest food pods, with maybe two dozen trucks or so right in the same space in the Downtown area.