Bring 3 cups water to a boil in a medium, heavy saucepan. Add barley; reduce heat, and simmer 30 minutes or until barley is tender. Drain and cool slightly.
Combine vinegar, 1 tablespoon brown sugar, 1 tablespoon soy sauce, 1 tablespoon oil, 1 teaspoon ginger, and 1 garlic clove in a large bowl, stirring well with a whisk. Add chard and barley; toss well to coat. Cover and chill 1 hour.
Preheat oven to 375°.
Cut tofu crosswise into 5 (1-inch-thick) slices. Place tofu slices on several layers of paper towels; cover with additional paper towels. Let stand 20 minutes, pressing down occasionally.
Cut each tofu slice into 1/2-inch cubes. Combine remaining 1 teaspoon sesame oil, remaining 2 tablespoons brown sugar, remaining 2 tablespoons soy sauce, remaining 1 teaspoon ginger, remaining garlic clove, and pepper in a medium bowl, stirring well with a whisk. Add tofu; toss to combine. Let stand 10 minutes.
Arrange tofu in a single layer on a foil-lined baking sheet coated with cooking spray. Bake at 375° for 30 minutes or until tofu is browned on all sides, stirring three times.
Divide barley mixture evenly among 4 plates, and top evenly with tofu. Sprinkle evenly with sesame seeds and onions.
Wonderful medley of flavors. Really enjoyed the combination of fresh ginger, garlic, and soy. The little bit of crushed red pepper added a nice touch of spicy heat. I didn't have barley in my pantry so I subbed my favorite grain, wheatberry. With the combination of the tofu and wheatberries, this dish was very hearty and served as the main course. Easy recipe to follow and it was delicious.