Cuban food is everywhere here in Miami but Versailles is probably the most famous and is really pretty darn good and reasonably priced.
(305) 444-0240
3555 SW 8th St, Miami, FL 33135
Here are some other good ones:
Sergio's
(305) 529-0047
3252 Coral Way · Coral Gables
La Carreta
http://lacarreta.com/
La Casita.
305) 448-8224
3805 Sw 8th St, Coral Gables, FL 33134
And if you really want to get a taste of the true Cuban experience:
Palacio de los Jugos. (The Juice palace).
(305) 264-4557
5721 W Flagler St · Miami
As for snorkeling, I think you'd probably want to go down to the keys for that as Miami isn't known for snorkeling. I guess you could do it but you'll probably want to go to John Pennekamp in Key Largo for that but that's about another 1-1/2 hours from Miami so you'd probably want to overnight if you do decide to do that or leave real early.
Have fun.
