There is a Burger King on the downstairs level and a place where you can get sandwiches, can't remember the name of it. We blew the lower level off and ate upstairs at Johney Burger, although there are a few places where you can get sandwiches. No restaurant per se. Johney Burger cost $38 U.S. for two burgers.
We try to get the to airport early enough so that after we check our bags we have time to walk to the end of the runway to Maho Beach and have ribs and a mango colada at Driftwood. The food isn't fabulous but it's not bad and beats spending more time at the airport.