The skiff rental shop will have a map and they'll tell you where and how. http://www.seaforthboatrental.com/skiff.htm

Edit: Sorry. I ought to be more helpfull. I've been successful using 3 inch grubs or swimbaits on a 1/4 oz head, cast, wind 3 or 4 times, let it drop, repeat. I've rented from the Coronado location and had good success fishing the boat moorings and the eel grass flats around the Coronado bridge.