Prepare the tofu: Press the tofu to remove excess water. Cut the pressed tofu into cubes. In a bowl, combine the cornstarch (or arrowroot powder), smoked paprika, garlic powder, cayenne pepper (if using), salt, and pepper. Toss the tofu cubes in the mixture until evenly coated.
Cook the tofu: Heat the oil in a large skillet or wok over medium-high heat. Add the coated tofu cubes and cook until golden brown and crispy on all sides, about 8-10 minutes. Remove the tofu from the skillet and set aside.
Make the sauce: In the same skillet, heat the oil over medium heat. Add the chopped onion and cook until softened, about 5 minutes. Add the minced garlic and grated ginger and cook for another minute until fragrant. Add the chopped bell pepper and cook for 3-4 minutes, until slightly softened.
Add remaining sauce ingredients: Stir in the coconut milk, red curry paste, soy sauce (or tamari), and maple syrup (or brown sugar, if using). Bring the mixture to a simmer and cook for 5-7 minutes, stirring occasionally, until the sauce has thickened slightly.
Combine tofu and sauce: Add the crispy tofu back to the skillet with the sauce. Stir gently to coat the tofu evenly.
Serve: Serve the spicy tofu with creamy coconut sauce over cooked rice or quinoa. Garnish with chopped cilantro, toasted sesame seeds, and lime wedges, if desired.