Mexican Street Corn Salad with Avocado

ears fresh corn (, husked and kernels cut from cob (3 1/2 cups))

vegetable oil

Salt

chopped red or green onion ((if using red run under water and drain to remove harsh bite))

slightly packed cilantro leaves (, chopped)

jalapeno pepper (, stemmed, seeded and minced)

garlic (, minced)

Cotija cheese (, finely crumbled)

mayonnaise ((light or regular))

fresh lime juice (, divided)

chili powder (, then more to taste (I used part ancho chili powder part regular))

medium avocados ((semi-firm but ripe) peeled, cored and chopped small)