*Waves enthusiastically to the south.* I am sadly out of touch with the state of cuisine generally in SFBA (miss it and my Chowhound partners in crime down there!) and specifically of jianbing but I liked Master Kong's very much. I have to say we haven't had much luck on previous visits to Portland in finding Chinese food variants that were to our liking but we are pretty spoiled for that at home so not complaining. I enjoy Bing Me as well if you are downtown and can avoid the lineups by going at off hours.
I googled XLB to get an idea of where you're staying and I can recommend one spot that appears to be relatively close: Grain and Gristle has one of my favourite burgers ever. They also have a great lineup of delicious beer from Upright, grayelf consort's favourite brewer. It is a lovely little neighbourhood spot, perfect for burg and beer at happy hour. 20 min walk from XLB.
A bit closer is the Mississippi Market Place food cart pod at Prost (11 min walk). Pastrami Zombie is there and has a lovely pastrami sandwich -- note that you can blessedly get a half sando if you are conserving belly space. If you like German style beer you can take it inside the pub, or there are covered tables outside with no beer purchase necessary. A new cart from Little Conejo in Vancouver WA is opening at some point and we will be checking that out too. Sadly cannot recommend the uber popular Matt's BBQ based on our visit at the end of May but to be fair we didn't have their most famous dish, brisket. If you have room and they haven't sold out, walk a bit further down Mississippi and get a rosemary raspberry old fashioned from Blue Star. I love that donut.
A leg-stretching 31 minute walk to Proud Mary on Alberta will net you a gorgeous Aussie style brunch with full-on Portland locavorishness, and some insanely delicious and impeccably presented coffees. They also have a great tea program if java isn't your thing. Superb service in a beautiful room rounds out the experience. If the founder and owner, Nolan, is about, give him a high five from grayelf. I've muled a fair bit of his coffee back to Vancouver for café and coffee friends here.
I haven't been yet because they are just now quietly, softly opening but based on previous work at their food cart, I'd say Georgian eats slingers Kargi Gogo would be a good bet. They took over the Big Egg's spot on Alberta, ten minutes walk past Proud Mary.
We didn't get a chance to try MF Tasty this trip but as it is only a three-minute walk from XLB it might be worth taking a look to see if it floats your boat. Paella is one of the specialties of this eclectic food cart. And there is a fine carnitas taco across the street at Que Sabrosa food truck if the ones here on blue corn tortillas seem too hipster for you ;-)
Hope some of these ideas are of interest/helpful, given you are so well traveled and have such wide food experience.