Boil rice without stirring until most of the liquid has evaporated and you can see small bubbles bursting on the surface of the rice. Immediately reduce the heat to the lowest setting, cover, and cook (do not stir, do not remove lid) for 15 minutes. Remove and discard bell pepper. Fluff rice with chopsticks or fork, then let cool and refrigerate for 1 day.
For the gallopinto: Heat remaining 2 tablespoons oil in large saucepan over medium-high heat until shimmering. Add remaining onion and cook, stirring, until softened and translucent, about 5 minutes.
Add rice and 2 cups beans to skillet and cook, stirring, until rice is evenly coated. Continue to cook, stirring, to allow flavors to meld and mixture to become slightly crisp, about 10 minutes. Cover and cook over low heat an additional 10 minutes. (See note.)
Special equipment
rimmed baking sheet, large pot with lid, zipper-lock bags, large heavy-bottomed saucepan with lid, large skillet with lid
