Heat a large skillet over medium high heat. Spray with cooking spray.
Add the tofu and cook for 10 minutes, stirring frequently, until tofu is crisp on the outside. Remove from pan.
Add the butter to the large skillet over medium heat.
Add in the corn and leeks and cook, stirring often, for 5 minutes.
Add the gochujang, garlic, and ginger and cook for 1 minute.
In a medium bowl combine the soy sauce, brown sugar, rice vinegar, and sesame oil. Mix well and add to the skillet along with the cooked tofu. Cook for 2 minutes.
Add in the cooked soba noodles and heat for 2-3 minutes.
Divide the tofu noodle mixture between 4 bowls. Top with cucumber and sesame seeds.