Heat oven to 375°F. Spray 12 mini muffin cups or mini tart pans with cooking spray.
Unroll dough on work surface; cut into 12 squares. Place each square in muffin cup, gently pressing in bottom and letting corners of dough overhang top of cup.
In small bowl, mix spinach and cheeses. Spoon 1 tablespoon filling into each crust-lined cup. Top each with 1 tomato slice. Fold corners of dough over tomato.
Bake 15 to 20 minutes or until golden brown. Serve warm.