Did the orange slices look like this?
http://www.etsy.com/view_listing.php?li ... d=11312266
Did the strawberries look like this?
http://www.etsy.com/view_listing.php?listing_id=5984449
Most of these are made with the melt and pour process. Sure maybe there's a way to do CP like that, but I know nothing about CP. The orange slices are made by embedding the wedges and using tube molds. I can't find a decent tutorial online right now, but think two tube molds, one slightly smaller than the other. The smaller with orange soap, cut lengthwise into wedges, then embedded in the bigger mold with white soap. More realistic orange slices can be acheived with an actual orange slice mold (usually they are chocolate/candy molds, some can be used for soap).
Soaps that are in the shape of strawberries would be best acheived with a mold, like this one:
http://cgi.ebay.com/Silicone-Strawberry ... dZViewItem
I'm not sure exactly what the watermelon soap you saw looked like. But there's this kind of mold:
http://cgi.ebay.com/BIG-SLICE-WATERMELO ... 18Q2el1247 which would require layering, and possibly painting on the seeds.
And then there's this kind of watermelon soap slice:
http://www.fishersworld.com/gboutique/i ... 0best1.jpg. My best guess on how to make it would require 3 very large in circumference tube molds, each about 1/2 an inch larger than the next. Straws stuck in the smallest mold (filled with pink/red soap on the outside of the straws) to create holes that you can later fill with black soap to create seeds. Then unmold the smallest and put it center into the next size tube mold and fill around it with white. Then unmold and put it in the largest mold centered and fill it with green. When it's done, slice about 1" thick and half or quarter the slices, whatever you are going for.
There are lots of tutorials and tips on different molds, techniques, embedding, etc. for melt and pour. Again, if you were wondering about CP or HP, I've got no clue. And if this is not what you were asking about, sorry! But I hope that helps!