For vinaigrette, stir together cornstarch and 1/4 cup water; blend thoroughly. In a small saucepan, bring remaining 3/4 cup water to boil; stir in cornstarch mixture; cook and stir to thicken. Remove from heat, cool completely and stir in remaining vinaigrette ingredients.
For salad, gently toss together pork, corn, tomatoes and herbs in large bowl.
Pour Vinaigrette over salad ingredients and toss gently. Serve on leaf lettuce.