Remove stems from spinach; wash leaves thoroughly and pat dry.
Position knife blade in food processor bowl; add half of spinach and process until finely chopped. Add remaining spinach; process until finely chopped.
Drain sun-dried tomatoes, reserving oil. Coarsely chop tomatoes; set aside.
Cook garlic and onion in 1/4 cup olive oil in a skillet over medium heat, stirring constantly, until tender and golden. Remove from heat. Add half of onion mixture, cheese, walnuts, and salt to spinach in food processor; cover and process until smooth, stopping once to scrape down sides. Add remaining onion mixture. With processor running, gradually add 1/4 cup plus 2 tablespoons olive oil through food chute in a slow steady stream; process until smooth. Stir in sun-dried tomatoes with oil.
Spoon pesto into small glass jars. Cover with a thin layer of additional olive oil. Cover jars with lids and store in refrigerator. Give each jar as a gift with a package of pasta.
Note: To serve, remove lid from jar. Microwave uncovered at HIGH 30 seconds to 1 minute or until throughly heated, stirring once. Toss 2 tablespoons pesto with 1 cup hot cooked pasta.