On a cutting board, using a sharp knife, cut off top and bottom of an orange. Moving the orange around and cutting top to bottom, slice off the peel and white pith. Working over a large bowl, cut in between membranes to remove orange segments, catching juice in bowl as you go. Repeat with remaining oranges and grapefruit.
Cut off top and bottom of pineapple.
Remove rough outside of pineapple by slicing it off from top to bottom.
Cut pineapple in half lengthwise, then cut each half in half again, also lengthwise. Slice out core.
Cut pineapple into chunks; add to bowl. Peel kiwis and cut in half lengthwise. Slice kiwis into bowl with other fruit. Gently toss fruit to mix. Cover and chill for at least 2 hours.
Sprinkle fruit salad with pomegranate seeds just before serving, if desired.
