Wrap firm tofu in a paper towel and gently squeeze (or place a heavy object on it) to remove excess water. Set aside to drain.
Prepare the dressing by mixing together ponzu soy sauce, sesame oil, white vinegar, olive oil, and a sprinkle of salt. Whisk together and set aside.
Put the sesame seeds on a saucepan and set it to medium heat. Toast for 3-4 minutes or until you smell a nutty aroma. Immediately remove from heat to prevent sesame seeds from burning.
Assemble the salad by mixing together the spring mix, toasted sesame seeds, and dressing. Crush the drained tofu with your hands (or a fork) and mix it into the salad.
Toss the ingredients together with your hands (or tongs).
Garnish the salad with additional sesame seeds if desired.