For polenta, in a 2 quart casserole combine cornmeal, the 1 cup cold water, and salt.
Slowly pour boiling water into cornmeal mixture, stirring constantly till the mixture is well blended.
Cook, uncovered, on 100% power (high) for 6 to 8 minutes or till very thick, stirring every minute.
Spray a 12x7 1/2x2 inch baking dish with nonstick coating.
Spread polenta in dish.
Cover; cool 45 minutes or chill overnight.
In a 2 quart casserole combine meat and onions.
Cook, covered, on high 5 to 7 minutes or till no pink remains, stirring once.
Drain; set mixture aside.
In the casserole combine corn, green pepper, Italian seasoning, and pepper.
Cook, covered, on high 5 to 6 minutes or till green pepper is crisp tender.
Stir in meat mixture and pimiento.
Cut polenta into 24 squares; arrange on platter.
Cook, covered with waxed paper, on 70% power (medium high) 4 to 5 minutes or till heated through.
Transfer to serving plates.
Cook meat mixture, covered, on high for 1 1/2 to 2 1/2 minutes or till hot.