Chopped Salad from Cowboy Ciao

This recipe comes from the Cowboy Ciao restaurant in Scottsdale, AZ (by way of epicurious.com)...

INGREDIENTS:
1 cup (packed) fresh basil leaves
1 cup mayonnaise
1 shallot, halved
1 cup buttermilk
1 tablespoon fresh lemon juice

1/3 cup grated Asiago cheese
1/3 cup dried currants
1/3 cup shelled pumpkin seeds (or try toasted pine nuts)

1 10-ounce package plain couscous, cooked according to package instructions (about 5 cups)
3 cups coarsely chopped arugula
1 pound plum tomatoes, seeded, diced (about 2 cups)
2 grilled chicken breast halves, diced (or can use cooked salmon instead)
2 cups fresh corn kernels (from about 2 ears) (or can use dried corn)

PREPARATION
Blend basil leaves, mayonnaise, and shallot in processor until smooth. Gradually blend in buttermilk and lemon juice. Season dressing to taste with salt and pepper. (Can be made 1 day ahead. Cover and refrigerate.)

Mix Asiago cheese, currants, and pumpkin seeds in medium bowl.

Using 1/6 of couscous, 1/6 of arugula, 1/6 of tomatoes, 1/6 of chicken, 1/6 of corn, and 1/6 of Asiago cheese mixture, form rows on each of 6 plates. Serve, passing dressing separately.