Coat a large skillet with olive oil cooking spray. Add the extra-firm tofu cubes in a single layer on the pan, saute on each side on medium-high heat until each side is golden brown and crispy.
Combine vinegar, sesame oil, soy sauce, peanut butter, 1 teaspoon sesame seeds, sugar, crushed red pepper, and garlic in a medium bowl. Whisk together until combined.