Rinse quinoa under cold running water. In a medium saucepan, combine 3/4 cup quinoa with 1-1/2 cups water. Heat to boiling over high heat. Stir in salt, reduce heat to low, cover, and simmer for 20 to 25 minutes or until liquid has been absorbed. Set aside.
In a large bowl, combine corn, beans, and salsa. Stir in quinoa, lime juice, and cilantro.