In a medium bowl, stir together the ginger, garlic, soy sauce, peanut butter, sriracha (if using), and smoked paprika until smooth. This will form a thick sauce base.
Bring a large pot of water to a boil and cook the udon noodles according to package directions. Reserve 1/2 cup of the noodle cooking water, then drain and set noodles aside.
While the noodles are cooking, heat the vegetable oil in a large skillet over medium-high heat. Add the tofu and cook for 2–3 minutes per side, or until golden brown and crisp.
Add the reserved noodle water to the sauce and mix until smooth. Add the cooked noodles and tofu to the bowl and toss gently to coat. Divide between bowls and top with green onions, sesame seeds, and fresh cilantro. Serve immediately.
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Notes
Want to add some veggies? These noodles are delicious with some steamed greens on the side like Pak choy, broccoli, or even wilted kale.