In 2-quart saucepan, heat water, wheat berries and salt to a rolling boil over high heat. Reduce heat to low; cover and simmer 1 1/4 to 1 1/2 hours or until tender. Drain; rinse with cold water to cool. Drain well.
Heat gas or charcoal grill. Place corn on grill over medium-high heat. Cover grill; cook 12 to 15 minutes, turning frequently, until tender. Cool slightly; cut corn from ears to measure about 2 cups.
In large bowl, stir together wheat berries, corn, tomatoes, spinach and onion.
In 1-cup measuring cup, mix vinegar, orange peel, orange juice, oil, honey, salt and red pepper with wire whisk. Stir into wheat berry mixture. Let stand 15 minutes before serving.