I love to leave a sliver of flesh on the rind, for a touch of sweetness and the beautiful gradient. The gradient that won't matter once ground into a delicious chutney. Yes, there is much to do with the remainder of fruit. The outer layers. The same way I'll dehydrate potato skins and grind them for a crust or powder; I'll kimchee, pickle, preserve, ferment and chutney a watermelon rind. It's a fun way to take apart an ingredient and reincorporate it, sort of deconstructed, in a dish. Imagine how much more fun watermelons would be to eat if they were bite size and eaten whole.
Preventing waste is something I grew up on, and finding creative ways to do it excites me even further. The chutney I made is inspired by my grandmother. Simply:
-Saute lemon slices (rind on) in a bit of olive oil; medium heat
-Add minced serrano chilies and ginger
-Add chopped watermelon rind (green and white)
-Cook for a couple minutes, until the lemon flesh has melted into the pan
-Add salt, sugar & white vinegar. Cook for 1 more minute
-Remove from heat. Blend all the ingredients in a blender or grind finely in mortar and pestle.
-Refrigerate. It's best served cold with just about any hearty dish. Preferably curries.