MIX first 3 ingredients until blended.
HEAT oil in large skillet on medium-high heat. Add peppers and onions; stir-fry 2 min. Add bok choy; stir-fry 1 min. Transfer to bowl; cover to keep warm.
ADD 1 Tbsp. of the dressing mixture and shrimp to skillet; stir-fry 2 min. Add vegetables and remaining dressing mixture; stir-fry 1 to 2 min. or until shrimp turn pink and vegetables are heated through.