Place chicken breasts into large plastic storage bag. Pound with a mallet or rolling pin to flatten to 1/4 inch uniform thickness. Season chicken with salt and pepper.

Heat grill and drizzle chicken with olive oil. Grill chicken on both sides until done, about 7 minutes per side. (Rotate halfway during grilling each side to ensure pretty grill marks.) Remove from pan. Allow to cool.

With a very sharp knife, shave kernels off each corn cob. Combine with the onion and celery. Set aside.

Mix together mayonnaise, sour cream, feta, and half-and-half. Stir in sugar, squeeze in lemon juice, and add salt and pepper. Stir, then taste. Add more salt if necessary; do not undersalt!

Slice chicken on the bias to create flat, randomly shaped pieces. Throw into a bowl with celery, onion, and corn. Stir to combine. Pour half the dressing over the ingredients and toss gently. Add more as desired, but don't overcoat the salad; should be light!

At the end, toss in the blueberries to lightly coat them in the dressing. Serve, then sprinkle individual helpings with feta.