Combine diced artichoke hearts and chopped spinach in a microwave-safe bowl with 2 tablespoons of water, cover bowl with plastic and poke a few holes in it to vent. Microwave vegetables on high for 6 minutes.

Combine remaining ingredients in a small saucepan. Add the steamed artichokes and spinach and place pan over medium/low heat, stirring often for 10 minutes or until simmering. Just before serving, you may wish to broil the dip in an oven-safe dish for 1 to 2 minutes (under high broil) or just until slightly brown on top. Arrange the diced tomato in a pile in the center of the dip and serve with crackers, toasted bread, pita chips or raw vegetables for dipping.