Poke holes in pork with a sharp knife. Insert peeled garlic cloves into holes. Brown roast on all sides in olive oil.
Peel or cut off peel of fruit. Put in blender or juicer. Blend until liquid. Add cumin and oregano. Blend.
Pour juice into slow cooker and add pork. Or if using a Ninja cooking system after browning pork in Ninja add juice. Turn setting to low and timer to 8 hours. Turn pork every couple of hours while cooking.
Remove pork and all liquid except one cup. Shred pork using forks to pull the meat a part. Add back to cooker and mix liquid with shredded pork. Heat for 10-15 minutes.