With a mortar and pestle or coffee grinder, crush the peppercorns, coriander seeds, dill seeds and red pepper flakes. Add the remaining steak rub ingredients and combine.
Brush the bison steaks on both sides with olive oil. Massage a generous amount of rub onto both sides of the steaks (you shouldn't need to use all of the rub). Marinate in the fridge for at least 1 hour or overnight.
Let the steaks sit at room temperature for 30 minutes before grilling. Preheat the outdoor grill to medium-high heat (about 400°F).
Place the steaks on the grill and cook until desired temperature, flipping once. (130°-135°F for medium rare/140°F-145°F for medium).
Remove the steaks to a cutting board, lightly cover with foil and rest for 5-10 minutes.