Soft Tacos With Chicken and Tomato-Corn Salsa

small red or white onion, finely chopped

ear of corn, steamed for five minutes

ripe tomatoes, finely chopped

to 3 jalapeño or serrano peppers (to taste), seeded if desired and minced

chopped fresh cilantro

fresh lime juice

Salt

boneless, skinless chicken breast, poached and shredded (about 2 cups)

corn tortillas

crumbled queso fresco or feta cheese