Place tofu slices on paper towels; pat dry. Set aside.
Place egg whites in a shallow dish. In another shallow dish combine pretzels and nuts. Dip tofu slices in egg whites, turning to coat. Dip tofu slices in pretzel mixture, turning to coat evenly. Coat a 12-inch nonstick skillet with cooking spray. Add 1 teaspoon of the olive oil to the skillet. Heat over medium-high heat. Add tofu slices; cook 4 to 6 minutes or until golden and crisp, turning once halfway through cooking time.
Meanwhile, for dressing, in a screw-top jar combine the remaining 4 teaspoons oil, vinegar, mustard, honey and slat. Cover and shake well.
In a large bowl combine spinach, apple and cranberries. Divide spinach mixture among four serving plates. Drizzle with dressing. Arrange tofu slices on top. Serve immediately.