Hi, These hot summer evenings make me wish for some Mexican places with outdoor seating and a full bar, or at least margaritas. Seafood (especially ceviche) would be a big plus.
Unfortunately there are not many options. La Cabana I thinks fits your priorities...Mex, patio, margaritas and the food is average...however many people on this board like it.
Don Antonio's (Pico and Barrington), El Cholo (Wilshire and 11th), and LuLu's (Main Street) all have outdoor patios and margaritas. I haven't had seafood at any of them. Don Antonios would be my first choice for other than seafood dishes.