Drain tofu; with a paper towel, press to expel excess water. Cut into 1-inch cubes.
In a medium bowl, mix together peanut butter, 3 ¾ tbsp sesame oil, the tamari, rice vinegar, sriracha, garlic and ginger.
Heat remaining 3 ¾ tsp sesame oil in a nonstick skillet or wok over medium heat. Add tofu and cook until golden, about 6 minutes. Add half the sauce and simmer 3 minutes, or until liquid is evaporated, flipping tofu occasionally to glaze in the sauce.
Peel zucchini. With a vegetable peeler, spiralizer or sharp knife, slice lengthwise into long, thin strips. Place in a bowl and toss with remaining sauce.
Top zucchini "noodles" with tofu and garnish with sesame seeds and chopped peanuts if desired.
