After two nights of casual friends-and-family service, Chris Cannon and Michael White’s big bet on Central Park South, Marea, opens to the public for dinner tonight. For the next week, the restaurant is in a preview mode, offering nearly three quarters of the menu (the raw bar isn’t quite ready yet, thanks to a construction mishap), all at a 20 percent discount. There are currently 56 covers on the books for this evening, and the plan is to slowly increase this number on successive nights as the kitchen can keep up. “It’s like taking a new car out on the road for the first time,” says the boss, “you don’t floor it right away.” If you want to score a table during discount week, you’ve got three options. First, you can try your luck calling the reservation line (212-582-5100); table availability will increase incrementally as the week goes on. Second, you can try walking in, but that’s annoying for the house this early on. Third (listen up!), you can get a table for two for Saturday or Sunday night — your choice — by e-mailing us with your prediction for the headline of Platt’s Marea review. We’ll be giving the table (not a free meal, but a guaranteed reservation) away by the end of the day. Creativity and alacrity will be rewarded.