Fill a large saucepan with water and bring to a boil. Add tapioca pearls and cook until tender and swelled, 15 to 20 minutes.
Meanwhile, in a small saucepan, combine sugar, lemon peel, and 2 1/2 cups water. Bring to a boil over medium heat, stirring, until sugar has dissolved. Remove from heat and add food coloring; stir until well combined. Transfer to a large bowl and add lemon juice and orange liqueur; stir until well combined.
Drain tapioca pearls and transfer to bowl with sugar mixture; stir to combine. Refrigerate until cool. Serve chilled with straws.
I put the tapioca pearls in lemonade or kool-aid for the kids.
Was thinking of making this for Hallowe'en this year, but I have kids, and wouldn't really want to give them something with Cointreau in it. What could I use as a substitute?