Cup of Yum
1. Using a mortar and pestle, grind the chillies into the salt until the salt is slightly pink and there are no longer any large chunks of the chilli peppers.
2. If you don't have a mortar and pestle, use a heavy-duty freezer bag instead. Put the salt and chilli in the bag and use a rolling pin to crush the chilli in the salt until its evenly distributed. You could also use the rolling pin directly on the salt and chillies on a hard surface like a cutting board, but then your rolling pin would have chilli oil on it and that might result in some spicy pie crust later on.
3. Store chilli salt in an airtight container.

To assemble the amuse bouche:

Cup of Yum
1. Cut watermelon into 1x2 inch slabs, about 1/2 inch thick. Sprinkle with a pinch of chilli salt, black pepper, and a couple pieces of chopped scallion.
2. Serve immediately as a fun little appetizer and palate cleanser!