Cook pasta according to package directions.  Drain and reserve the liquid; set aside covered.

Grate 1 teaspoon of lemon rind and add to ricotta cheese, 1/4 teaspoon salt, 1/4 teaspoon pepper; set aside covered.

In a large skillet, heat 1 tablespoon oil over medium heat.  Chop pepper and add to skillet; saute for 2-3 minutes.  Add 1/4 teaspoon salt and chopped walnuts.  Slice or mince garlic, add to skillet and saute for 1-2 minutes.  Stir in 1 tbsp olive oil, 1 tablespoon juice of lemon; add pasta, 1/4-1/2 cup of reserved pasta water, spinach, and the ricotta cheese; cook for 1 minute while stirring and allow spinach to begin wilting and cheese to be heated through. Remove from heat.

Serve with orange wedges on the side.