Heat the olive oil in a large skillet over medium-high heat. Add the onion and bell pepper and cook, stirring, until softened, 3 to 5 minutes. Stir in the garlic, gingerroot, and tomato paste. Cook, stirring, for 1 minute.
Add the bison and season with salt and black pepper. Cook, breaking up the meat with a wooden spoon, until browned, about 3 minutes. Stir in the chicken broth mixture, and use a wooden spoon to scrape up any brown bits from the bottom of the skillet. Bring to a boil, then reduce the heat to a simmer. Cook until slightly thickened, 3 to 5 minutes. Add a dash or two (or three or four . . . ) of sriracha. Remove the pot from the heat and add the lime zest, lime juice, and cilantro. Taste and season with additional sriracha and/or lime juice, if desired.
Spoon the grains into bowls. Top with the meat mixture. Sprinkle with cilantro and peanuts, and drizzle with sriracha, if you’d like. Serve with lettuce leaves for wrapping.