In 2-quart saucepan, place eggs in single layer; add enough cold water to cover eggs by 1 inch. Cover; heat to boiling. Remove from heat; let stand covered 15 minutes. Drain eggs. Immediately run cold water over eggs until completely cooled. Peel and chop eggs.
Meanwhile, in large (4-quart) microwavable bowl, place frozen cauliflower and frozen peas and carrots; cover with microwavable waxed paper. Microwave on High 20 to 25 minutes, stirring once halfway through microwaving. Drain vegetables in colander; rinse with cold water to cool. Place colander over same large bowl; refrigerate at least 30 minutes or until cooled.
In small bowl, mix mayonnaise, sugar, salt, pepper, 1/8 teaspoon of the paprika, the vinegar and mustard; set aside.
Remove vegetables from refrigerator; discard any liquid in bowl. Pat drained vegetables dry with paper towels; chop any large cauliflower pieces into 3/4-inch chunks to resemble chopped potatoes. Place cauliflower, peas and carrots in same bowl. Add celery, onion and chopped eggs.
Pour mayonnaise mixture over salad; stir until vegetables and eggs are well coated. Sprinkle remaining 1/8 teaspoon paprika over salad. If desired, cover and refrigerate at least 1 hour or until well chilled before serving.