Slice tofu into 1/2-inch-thick strips and press between paper towels to remove excess water; leave to drain while preparing vegetables.
Heat 2 tablespoons peanut oil and sesame oil in a skillet over medium-high heat. Add green bell peppers, onions, and carrots; saute until peppers and carrots are tender and onions are golden brown, 5 to 10 minutes. Remove from heat, mix in green onions and garlic, and cover with a lid.
Chop tofu into bite-sized chunks. Heat remaining peanut oil in a skillet over medium heat. Add tofu and cook until golden brown, about 10 minutes.
Combine peanut butter, water, sriracha sauce, soy sauce, salt, and black pepper in a blender and blend until smooth to make the peanut sauce.
Transfer tofu and peanut sauce to the skillet with the vegetables. Heat over low heat until warmed through, about 5 minutes.