For the tofu: Sandwich each piece of tofu between 2 sheets of paper towels and place on a plate. Top with a second plate and weigh the plate down with a can or a heavy book to press any liquid out of the tofu. Set aside, changing the paper towels every 30 minutes, for 2 hours.
For the lime sour cream: Whisk together the sour cream and lime zest and juice in a small bowl, then transfer to a squeeze bottle or container. Refrigerate until ready to serve.
For the salsa: Combine the peaches, cucumber, cilantro, jalapeno, lime juice and onion in a large bowl and season with salt and pepper. Set aside.
For the black beans: Saute the onion in the oil in a large skillet until translucent, 5 to 7 minutes. Add the garlic, chili powder, cumin and red pepper flakes. Cook for 2 minutes, then stir in the tomato paste. Add the beans and 1/2 cup water. Bring to a simmer, then reduce the heat to low and cook for 10 minutes. Season with salt and pepper. Use a potato masher or the back of a wooden spoon to partially mash the beans. Cover to keep warm or reheat when ready to serve.
Make the tofu: Preheat an outdoor grill or grill pan to medium-high.
Cut the tofu into 1-inch-wide logs. Mix the chili powder, garlic powder, onion powder, paprika, salt and pepper together in a bowl, then sprinkle the tofu on both sides with the spice mix. Brush the tofu with a generous amount of olive oil. Oil the grill grates, then place the tofu on the grill and cook until heated through, 2 to 3 minutes per side. Transfer to a plate.
To build each taco, spoon some beans onto a tortilla. Top with the tofu and salsa. Drizzle with lime sour cream and serve immediately.
Ryan's Pickled Red Onions:
Yield:about 2 cups
Place the onions in a jar. Whisk the vinegars together with the sugar, salt and 1 cup water in a bowl until dissolved. Add the peppercorns. Pour over the onions and refrigerate for 2 to 3 hours (see Cook's Note). Pickled onions keep about 2 weeks in the fridge.
If using smoked tofu, omit the spice blend. You can also boil the liquid mixture, then pour over the onions, if you want them to have a little less "bite."