From ikitesurf.com:
Any suggestion or restrictions regarding kiting off Miami Beach? I will be staying on Collins Ave. Do I need a car or can I just going anywhere along the beach?
Technically, all of Miami Beach is banned to kiteboarding. At the same time they don't appear to be actively enforcing the ban at this time. You would do well to avoid areas with lifeguards, launch and ride out past 300 ft. from shore or more, and stay out until time to come in. Too many guys in the past rode close to swimmers creating the ban in the first place.
Collins Ave. is a long road. What part of Collins will you be staying at?
Some guys ride south of 5th St. and others around 77th St., Northshore Park.
Other ideas intended to preserve access appear in:
http://www.fksa.org/viewtopic.php?t=2
Keep low key and have fun.