Whisk together all sauce ingredients and set aside.
Heat sesame oil over medium heat in a large skillet or wok. Add scallions and tofu. Cook for 5 minutes.
Add peppers and green beans. Cook for about 10-15 more minutes, until tofu is browned and veggies are cooked through.
Reduce heat to low and add the noodles. Pour the sauce over top and toss everything together. Cook for about 3 more minutes, until the noodles are warmed through and evenly coated in the sauce.
Turn off heat. Top with cashews, scallions and chili oil (if using). Divide out and serve.
