In A Skillet, Combine The Vegetables, Water, Onion And Salt. Bring To A Boil Over Medium Heat. Stir In The Soup, Rice, Tuna, Parsley And Marjoram. Reduce Heat; Cover And Simmer For 5-10 Minutes Or Until The Rice Is Tender And The Liquid Is Absorbed. Stir In Lemon Juice. Serve Immediately.