I've written favorably about Paseo in Fremont before, but there is a second location that has opened near Golden Gardens Park in the last few years and I recently stopped by for what I can pretty confidently say is just about best sandwich in the city.
First I should mention that the new location is simple, but gets the job done and is great for summertime: You order your food from a bright pink shack, then eat it outside at some covered picnic tables.
What I love about Paseo is that they have an awesome vegetarian sandwich that absolutely lacks in no hedonistic way. It comes on a toasty hot baguette and is filled with marinated grilled tofu, amazing (somewhat pickled?) grilled onions, lettuce, and my favorite part: grilled jalapeno slices that have had some sort of magic infused in them that make them addictingly fantastic. All of this is slathered in some kind of deliciously flavored buttery mayonnaise-y sauce (I try not to think too hard about this part), and some lettuce and the result is 100% pleasure.