In a large mixing bowl, whisk together the flour, baking powder, and fine salt. Pour in the warm water and 2 tablespoons of vegetable oil. Stir with a wooden spoon or your hands until a shaggy dough forms. The mixture should be soft and slightly tacky but not runny. If dry flour remains at the bottom of the bowl, mix it into the dough with lightly dampened hands.

Turn the dough onto a lightly floured work surface. Knead gently for about 2 minutes, just until it becomes cohesive and relatively smooth. Avoid adding excessive flour or kneading for too long, as this can make the finished bread tough. Return the dough to the bowl, cover it with a clean kitchen towel or plastic wrap, and let it rest at room temperature for 20 minutes.

While the dough rests, heat a large 12-inch skillet over medium-high heat. Add the ground beef and diced onion. Cook for 6–8 minutes, breaking the beef into small crumbles, until the onion softens and the beef is browned. Drain any excess grease if necessary.

Reduce the heat to medium: Add the minced garlic, chili powder, cumin, smoked paprika, kosher salt, and black pepper. Stir for about 30 seconds, until the garlic and spices become fragrant. Add the tomato paste and cook for another minute, stirring to coat the beef evenly.

Pour in the water and stir in the drained pinto beans. Simmer gently for 4–5 minutes, until the liquid has mostly reduced and the filling is moist but not watery. The ground beef must reach an internal temperature of 160°F (71°C) . Reduce the heat to low to keep the filling warm while you prepare the fry bread.

Shred the lettuce, dice the tomatoes, and place them in separate serving bowls. Set out the shredded cheddar, sour cream, salsa, and optional cilantro and jalapeño. Refrigerate the cold toppings if you are not assembling the tacos immediately.

Transfer the rested dough to a lightly floured surface and divide it into 6 equal portions. Shape each portion into a ball, then flatten it with your hands or a rolling pin into a round approximately 6–7 inches wide and about ¼ inch thick. Make a small opening in the center of each round with your fingers. This allows steam to escape and helps prevent the bread from developing one enormous air pocket while frying.

Pour enough frying oil into a deep, heavy-bottomed skillet to reach a depth of approximately ½ inch. Depending on the skillet, you may not need all 3 cups. Heat the oil over medium to medium-high heat until it reaches 350–365°F (175–185°C). Use a thermometer to monitor the temperature. Oil that is too cool will produce greasy bread, while excessively hot oil can brown the outside before the center cooks.

Carefully lower one round of dough into the hot oil, laying it away from you to minimize splashing. Fry for approximately 1–2 minutes per side, turning once, until puffed and evenly golden brown. Adjust the burner as needed to maintain the oil temperature. Lift the bread from the oil with tongs or a spider strainer and allow the excess oil to drain.

Transfer the cooked fry bread to a wire rack set over a rimmed baking sheet. Continue frying the remaining dough, one piece at a time or as many as can fit without crowding the skillet. The finished bread should have a lightly crisp surface with a soft, cooked center. If the exterior browns too quickly, reduce the oil temperature slightly before frying the next piece.

Place one warm piece of fry bread on each serving plate. Spoon approximately one-sixth of the seasoned beef and bean mixture over each round. Add the shredded lettuce, diced tomatoes, and cheddar cheese. Finish with sour cream, salsa, and any optional toppings.

Serve the Navajo tacos while the fry bread is still warm and crisp. For a gathering, arrange the fry bread, beef filling, and toppings separately so guests can assemble their own tacos.