Preheat oven to 350°. Line 2 regular-size muffin trays with baking cups. In a large bowl, mix flour, baking powder, soda, salt, and cinnamon; set aside. In another large bowl, beat together eggs, sugar, vanilla, and oil. Add zucchini, and mix well. Add flour mixture, and blend. Stir in pineapple and walnuts. Pour batter in equal parts into muffin cups. Bake about 20 minutes, or until toothpick inserted into center of muffin comes out clean.