Boston-area chefs are infusing foods including cheesecake, strawberries and tomatoes with cold smoke using a smoke gun that imparts flavor without cooking the food. "It's the flavor of the Neanderthals," said chef Tony Messina of Uni sashimi bar. "That's one of the appeals of it. There's something primal about it. If you add smoke to something, it's going to evoke the desire to eat more food."