1. Combine bison, ginger, and garlic in a large frying pan over medium heat. Cook, stirring to break up meat, until browned, 6 to 8 minutes. Add bean sauce and hoisin and stir just until combined. Stir in water chestnuts and onions.
2. Spoon bison mixture into a serving bowl. Put peanuts in a small bowl and set lettuce leaves on a platter. Serve with Sriracha.
Note: Nutritional analysis is per serving.