Press tofu firmly with paper towels to release moisture. (I typically do this to the whole block and then slice it into 5 strips and press it again to remove as much water as possible.) Slice tofu into cubes.
Combine cashew butter, soy sauce, vinegar, sugar, sesame oil, sriracha, ginger and 1 Tbsp water in a bowl; stir with a whisk.
Heat 1 Tbsp. vegetable oil in a large skillet over medium. Cook sweet potato noodles for 7-8 minutes, tossing often until slightly softened. Add 1-2 Tbsp of water after a few minutes to create steam in the pan. Once tender, transfer to a bowl and add HALF the sesame cashew sauce. Toss to combine.
Add remaining 1 Tbsp vegetable oil to pan. Cook tofu for 7 to 8 minutes, turning to brown all sides. Add garlic and remaining half of sauce; simmer until tofu begins absorbing the sauce. Add lime juice and keep gently tossing tofu and scraping browned bits. (You should end up with crispy browned crusts on the tofu and browned bits in the pan.)
Top sweet potato noodles with tofu and add optional toppings as desired.