Press the extra firm tofu for 15 minutes to remove excess moisture and then cut into 1-inch cubes.
In a small bowl, whisk together the tamari, rice vinegar, grated ginger, and minced garlic to create the stir-fry sauce.
Heat the toasted sesame oil in a large non-stick skillet or wok over medium-high heat.
Add the tofu cubes to the hot skillet and sear for 8-10 minutes, turning occasionally until all sides are golden and crispy.
Add the broccoli florets, sliced red bell pepper, and snap peas to the skillet with the tofu.
Sauté the mixture for 4-5 minutes until the vegetables are tender-crisp and retain their bright color.
Pour the prepared sauce over the tofu and vegetables, tossing quickly for 1 minute to ensure everything is evenly coated.
Remove from heat and sprinkle with sesame seeds and red pepper flakes before serving.