1Combine raw ground beef, beans, oregano and cumin seeds; mix well. Fill uncooked manicotti shells with meat mixture. Arrange in 13- by 9- by 2-inch baking dish. Combine water and picante sauce; pour over manicotti shells.
2Cover with vented plastic wrap. Microwave with 650 watts for 10 minutes, turning dish half turns after 5 minutes. Using tongs, turn shells over. Microwave, covered, with 350 watts for 17 to 19 minutes or until pasta is tender, giving dish half turn once.
3Combine sour cream and onions and spoon down center of casserole; top with cheese. Microwave with 650 watts for 2 to 3 minutes or until cheese melts.