Press and drain tofu using a tofu press. If you don't have a tofu press, place tofu into a small colander. Top with a paper towel, then add a heavy cast iron pan on top of the tofu. Place the colander over a bowl to drain.
While the tofu drains, prepare the green beans. Place the frozen beans on a baking sheet. Roast in a preheated 400 degree F oven for 10-15 minutes, tossing half way. Set aside.
In a small bowl, mix 1 teaspoon of the corn starch with the soy sauce, sriracha, honey and garlic powder. Set aside.
Cut drained tofu into 1-inch cubes. Add 3 teaspoons of corn starch into a medium-sized bowl. Add the cubed tofu and toss to coat.
Heat a large pan over medium high heat. When hot, add 2 teaspoons of oil to the pan, then quickly add the tofu cubes. Spread the tofu in the pan so it is in one layer. Allow to brown on each side, turning once.
Remove tofu from pan, transferring to a small bowl. Add another teaspoon of oil to the pan and add the green beans. Stir-fry for 1-2 minutes. Add the tofu back to the pan, and pour the sauce over the tofu-green bean mixture. Stir fry for another 2 minutes.