Add all ingredients to the jug of your blender and blend on high for 10-15 seconds.
Refrigerate blender jug for 30 minutes and then pulse for 5 seconds, adding 3-4 ice cubes as desired.
Pour into a chilled rocks glass. Garnish with a strawberry and lemon wedge. Serve with a straw.
In saucepan over medium-high heat, bring rhubarb, sugar, 1 cup water and lemon peel to boil, stirring occasionally. Reduce heat to medium-low and simmer, stirring occasionally, until rhubarb breaks down and mixture thickens slightly, about 5-8 minutes.
Strain into bowl, pressing solids gently to extract liquid; discard solids. Cover and refrigerate until chilled. Make-ahead: Refrigerate in airtight container for up to 5 days.