Mix cumin, dark chili powder, smoked paprika, cayenne pepper, garlic powder, kosher salt, and cracked black pepper in a small bowl. Set aside.
Preheat a medium-sized skillet over medium-high heat until very hot. Add oil and swirl the pan to coat it evenly. Add ground bison meat, crumbling the meat with a wooden spoon. Cook bison, occasionally stirring until it is almost completely browned; about 8-10 minutes. (Because bison is naturally leaner than most other meats, it is very important to retain all of the juices in the pan at this step!)
Add dry seasonings and water to bison. Bring mixture to a simmer and stir to allow the meat to absorb water, about 3-5 minutes.
Make pico by combining quartered cherry tomatoes, diced red onion, chopped fresh cilantro, diced jalapeno, fresh lime juice, and salt in a small bowl—taste adjusting for salt and lime juice, to taste. Refrigerate while heating tortillas.
Heat corn tortillas on a grate over an open flame, flipping on both sides until slightly charred in spots, about 30 seconds each side. Alternatively, tortillas can be heated in a hot nonstick skillet for 30 seconds on each side. Watch for the corn tortillas to puff and then flip them. With either method, cover tortillas with a towel and rest for 5 minutes before serving. This allows tortillas to steam.
To assemble tacos, place 1 oz of seasoned ground bison into each shell and top with pico and your choice of other toppings like mashed avocado, crumbled cotija cheese, sour cream, chopped cilantro, sliced jalapenos, and a fresh squeeze of lime.