Adjust the oven rack to the middle position and heat the oven to 400°F. Combine the water and baking soda in a large bowl. Add the beef and mix until thoroughly combined; set aside. Heat 1 tablespoon of the oil in a 12-inch nonstick skillet over medium heat until shimmering. Add the onion and cook, stirring occasionally, until softened, 4 to 6 minutes. Stir in the chili powder, paprika, cumin, garlic powder, and tomato paste and cook until fragrant. Add the beef and cook, breaking it up, until no longer pink. Off the heat, stir in the 1/2 cup cheddar until melted and the filling is cohesive; season with salt to taste. Brush the corn tortillas on both sides with some of the oil and warm them in the oven until pliable. Spoon filling onto one half of each tortilla and fold the other half over to enclose. Repeat with the remaining tortillas and filling. (Filled tortillas can be covered and refrigerated for up to 12 hours.) Set a wire rack in a rimmed baking sheet and line with a double layer of paper towels. Heat the remaining 1/4 cup oil in the now-empty skillet over medium-high heat until shimmering. Arrange 6 tacos in the skillet facing the same direction, open sides facing away from you. Cook, adjusting the heat so the oil actively sizzles, until crispy and deeply browned on one side, 2 to 3 minutes. Using tongs and a thin spatula, carefully flip the tacos and cook until deeply browned on the second side, 2 to 3 minutes. Transfer to the prepared rack, blot the tops, and keep warm in the oven. Return the skillet to medium-high heat and cook the remaining tacos. To garnish, open each taco like a book and load with toppings; close to eat. Serve immediately, passing extra cheddar, lettuce, tomato, sour cream, jalapeños, and hot sauce separately.