Drain and rinse beans and add to a large bowl. Add 1 cup corn as well.
Wash and dry all produce. Dice Roma and heirloom tomatoes into 1” chunks. Add to the bowl.
Slice the avocado in half and discard the pit. (Best way to do this is gently whack your knife into the pit and use that to lift it out. If ripe, should come out easily.)
Roughly dice onions and add to the salad.
Crumble the feta cheese into the bowl and toss together to combine.