Three ingredients. Two steps. What could be easier?
2 lemons, peels removed
1 lime, peel removed
flesh of 1/2 a small seedless watermelon
(1) Blend or food process to puree all the fruit together.
(2) Strain through a fine mesh sieve.
Caveat: actually, the last step can get messy if you try to coordinate straining from colander or sieve into a pitcher. Trying to balance a funnel between a sieve and pitcher to keep the juice directed was an impossible balancing act. At least for me. The easier method (that dirties more dishes) is to use the sieve to strain the puree into a mixing bowl with one of those slight spouts or indents and then use that spout to pour from there into the pitcher or carafe. Or strain into your punch bowl and serve with a ladle.