Place a 9×13 inch metal baking dish in the freezer for 15–20 minutes to chill while you prepare the mixture.

Add the cubed watermelon, fresh lime juice, lime zest, honey (or agave), and sea salt to a blender. Blend on high for 30–45 seconds until completely smooth. Taste and adjust sweetness or lime juice as needed.

Pour the blended mixture through a fine mesh strainer into the chilled baking dish, using a spatula to press through as much liquid as possible. Discard any fibrous solids remaining in the strainer.

Place the baking dish in the freezer uncovered. After 45 minutes, use a fork to scrape and stir the mixture, breaking up any ice crystals that have begun to form around the edges.

Continue freezing and scraping with a fork every 30–45 minutes for approximately 3 to 4 hours total, until the entire mixture has transformed into light, fluffy, separate ice crystals throughout — it should look like shaved ice or snow with a vivid pink color.

Once the granita has reached the desired flaky texture, cover the dish tightly with plastic wrap or transfer to an airtight container. Freeze until ready to serve.

To serve, use a fork to scrape and loosen the granita into fluffy mounds and spoon into chilled glasses or bowls. Garnish with fresh mint leaves and a thin lime wheel if desired. Serve immediately.