Remove the walnuts from the microwave and set aside to cool. Make the sweet red-wine vinaigrette dressing (recipe follows). Core and slice the tomatoes and set aside.
Place the lettuce and tomatoes into a bowl or individual salad plates. Shake the dressing to recombine and drizzle to taste over the salad. Toss the salad to coat with the dressing and then distribute the chicken, grapes, blue cheese and walnuts over the salad.
Sweet Red Wine Vinaigrette
1/2 cup red wine vinegar
1 cup extra-virgin olive oil
2 tablespoons sugar
1/2 teaspoon salt
1/4 teaspoon ground black pepper (more or less to taste)
Combine the vinegar, oil, sugar, salt and pepper in a 2-cup jar that has a lid (or a bowl that will allow vigorous whisking). Shake until well-combined. Makes about 1 ½ cups. Leftover dressing will keep, covered, in the refrigerator, for several weeks.