Spray the onion and sliced peppers with the remaining oil. Cook on the char grill or barbecue, turning occasionally, for 5 minutes or until tender and lightly charred.
Cook tortillas for 30 seconds on each side or until beginning to char.
Arrange slices of lamb, beef, onion and peppers on a large serving board with salsa, guacamole, tortillas, sour cream and lime wedges.