To make watermelon puree: Remove seeds from watermelon and cut into large chunks. In blender, process until smooth.
In large, heavy saute pan over medium-high heat or electric skillet set to 325 F, heat oil.
Saute mini meatballs until browned and hot. Reduce heat to low.
Mix barbecue sauce and watermelon puree. Pour over meatballs and simmer 2-3 minutes. Serve hot.