Bring 6 cups water to boil in medium saucepan. Meanwhile, heat remaining oil in same skillet. Add peppers; cook and stir 4 to 5 min. or until crisp-tender. Add peanut butter mixture to skillet; cook 1 to 2 min. or until well blended, stirring constantly. Return tofu to skillet; cook and stir 1 to 2 min. or until heated through. Remove from heat.