Mmmm... I have never been disappointed by the food (or service) at Pepper Sisters. Bear in mind, you should come hungry.
I have not been able to stray from a few "standards" that I've adopted while dining at Pepper Sisters. The Chicken Elote Enchilda is what my wife always gets; I usually get the Blue Plate which is a chicken enchilade with blue corn tortillas (hence the name), cheese, olives, and I'm not sure what else in the enchilada. It comes with a salad, beans, and posole. Accompanying sauces vary in spiciness... I would imagine they'd be very receptive to accomodating any requests in that manner. The wait staff is always VERY professional and really make you feel at home.
Most dishes at Pepper Sisters come with 2 of the following: rice, black beans, baked beans, posole. All 4 are wonderful; my favorite is the posole. As a NW born and bred Scandinavian, hominy is not usually a huge draw for me, but when Pepper Sisters does it up in posole, you don't want to miss it.
Finally, I have a healthy appetite and I have not yet been able to indulge in a dessert after a meal at Pepper Sisters. The sopaipillas (spelling?) are dessert enough. They're a deep fried dough that puffs up and the way I usually eat them is to slice them and fill up the puffed up gap with the wonderful honey-butter that comes with them. I don't know why they bother with a dessert menu after that.