Step 1Saute shallots in olive oil in small skillet over medium-low heat until they begin to turn golden, 1 to 2 minutes. Stir to prevent burning. Add tomato and saute until cooked through, stirring, 1 to 2 minutes. Stir in vegetable and chicken broths, water and 1/2 teaspoon oregano. Heat to boiling. Reduce heat and simmer until liquid is reduced to 1/2 cup, about 5 minutes. Stir in salt and lemon juice. Set dressing aside to cool to room temperature.
Step 2Just before serving, lightly sprinkle cheese slices with 1/4 teaspoon oregano. Add cheese to hot skillet sprayed with nonstick cooking spray and cook over medium-low heat until browned, 1 1/2 minutes. Turn and brown second side, about 1 minute.
Step 3For each serving, place 1 slice cheese on 1 cup salad greens. Sprinkle pepper over salad, and top with tomato vinaigrette.