1. Cut tofu crosswise into 3/4-inch thick slices; cut each slice crosswise into thirds. Arrange strips in a single layer on sheet of wax paper. Sprinkle with salt and half the seeds.
2. Heat 1 teaspoon oil in nonstick skillet over medium-high heat; add half the tofu, seeded side down. Sprinkle with half of the remaining seeds; brown 2 minutes. Turn slices; add 1 teaspoon oil to pan. Brown 2 minutes. Transfer to plate. Repeat with 2 teaspoons oil, tofu and seeds.
3. Heat remaining oil in skillet. Cook 1/4 cup green onions 2 minutes. Whisk in peanut butter, teriyaki sauce, and reserved 1/3 cup pasta water. Toss pasta with watercress and peanut sauce. Divide among 4 plates; top with tofu and remaining green onions. Makes 4 servings.