For fast, cheap and delicious Carne Asada burritos, mahi tacos, and the like, try La Sirena Grill in Laguna Beach (Mermaid St, in the village behind Sorrento Grille).
Unbelievably good and cheap Chinese food at S.W. Bar-B-Q Seafood, 5406A Walnut Ave, Irvine. Always crowded.