On a large plate, combine 1 tablespoon flour, salt, and pepper. Set aside. In a small bowl, combine cheese, lemon juice, and oregano. Set aside.
With a meat mallet, pound each chicken breast to 1/2 inch thickness. Spread cheese mixture on each chicken breast, leaving 1/2 inch border. Fold chicken breasts in half; secure each with toothpick. Coat chicken breasts with flour mixture.
In large skillet, heat oil over medium heat. Cook chicken breasts for 1 to 2 minutes on each side, until golden. In a small bowl, whisk together 1 1/2 cups water, chicken bouillon cube, and remaining flour; pour over chicken breasts in pan. Add spinach and tomato to skillet, and bring to boil. Cover, reduce heat to low, and simmer for 8 to 10 minutes, or until chicken is no longer pink inside. Discard toothpicks before serving.