Heat oven to 250 degrees F. Drain tomatoes, reserving oil. Place focaccia on large baking sheet and brush with 2 teaspoons of the oil. Cut in 8 wedges. Arrange wedges in circle. Place in oven to warm.
Meanwhile, in a 12-inch skillet cook sausage over medium-high heat, breaking up with a wooden spoon. Drain sausage in a colander, reserving 2 teaspoons drippings in skillet. Cook spinach in drippings just until wilted.
Set oven to Broil. Top warmed focaccia with cheese, dried tomatoes, sausage, and spinach. Broil, 4 to 5 inches from heat, for 3 to 5 minutes or until cheese is softened and toppings are heated through. Drizzle wedges with additional oil from tomatoes (optional). Makes 4 servings.