Use a chef's knife and cutting board to cut the watermelon into roughly 1-inch cubes, removing the rind if desired. Arrange prepared watermelon cubes on the cutting board.
4 cups watermelon, cubed
Transfer the watermelon cubes into a blender jar. Add the measured lime juice and sea salt.
4 cups watermelon, cubed
Secure the lid on the blender and blend on high speed until the mixture is smooth but still slightly grainy from the seeds, about 30 seconds. Listen for a consistent blending sound and observe the mixture becoming uniformly red.
Pour the blended watermelon liquid through a fine mesh sieve into glasses to remove large seed fragments and achieve a smoother texture, pressing gently with a spoon to extract maximum liquid.
Serve immediately in chilled glasses, optionally garnished with lime wedges or mint leaves. The drink should be vibrant red with a lightly grainy texture from the seeds.
