Preheat the oven to 425 degrees F. Grease a sheet pan with non-stick cooking spray.
Pat the tofu with a paper towel. Wrap with a dry paper towel and place a cast iron pan or cutting board on top to remove more liquid. Let stand for 15 minutes. Cut the tofu into 1-inch cubes.
Arrange the tofu in a single layer on the sheet pan and bake for 10 minutes. Take the pan out of the oven, turn over the tofu and add the asparagus.
Continue cooking until the tofu is lightly browned and the asparagus is tender and bright green but still crisp, about 7-8 minutes.
While the tofu and asparagus are in the oven, make the sauce. In a small saucepan over medium heat, whisk together the soy sauce, tahini, maple syrup, rice vinegar, sesame oil, garlic, ginger, red pepper flakes, salt and pepper. Simmer for 2 minutes.
In a small bowl, stir together the cornstarch and water and whisk into the sauce. Continue simmering until the sauce thickens, about 2 minutes.
Spoon the sauce onto the sheet pan and toss around the tofu and asparagus, so they are coated. Serve extra sauce on the side.
Sprinkle on the scallions and sesame seeds.
Serve with brown rice or quinoa.