Step 1: For the Fry Bread, in a large bowl, whisk together the all-purpose flour, baking powder, and 1 teaspoon salt. Gradually add 1 1/4 cups warm water, mixing until a soft, shaggy dough forms. Do not over-knead.
Step 2: Cover the bowl with a clean kitchen towel and let the dough rest for at least 30 minutes at room temperature. This allows the gluten to relax, making the bread more tender.
Step 3: While the dough rests, prepare the fillings. For the Ground Beef, in a large skillet, brown the ground beef over medium-high heat, breaking it up. Drain any excess grease.
Step 4: Stir the taco seasoning and 1/4 cup warm water into the beef. Bring to a simmer and cook for 5-7 minutes, until the liquid has mostly absorbed and the beef is well seasoned.
Step 5: For the Spiced Pinto Beans, in a medium saucepan, heat 1 tablespoon olive oil over medium heat. Add the rinsed/drained pinto beans, cumin, 1/2 teaspoon salt, black pepper, and onion powder.
Step 6: Sauté the beans for 5-7 minutes, stirring occasionally, until heated through and fragrant. Lightly mash some beans with a spoon if desired.
Step 7: Heat about 2-3 inches of vegetable oil in a large, deep skillet or Dutch oven over medium-high heat until it reaches 350°F (175°C).
Step 8: Divide the rested fry bread dough into 10-12 equal portions. On a lightly floured surface, gently flatten each portion into an oval or circular shape (about 6-8 inches in diameter and 1/4 inch thick). Make a small hole in the center.
Step 9: Carefully slide one or two pieces of flattened dough into the hot oil. Fry for 1-2 minutes per side, or until golden brown and puffed. Remove and place on a paper towel-lined wire rack to drain.
Step 10: To assemble the tacos, place a warm piece of fry bread on each plate. Spread with a layer of spiced pinto beans, then add the seasoned ground beef.
Step 11: Top with shredded lettuce, diced tomatoes, shredded cheese, and a dollop of sour cream or Greek yogurt. Garnish with fresh cilantro and any other desired toppings. Serve immediately.