Make the strawberry puree: puree strawberries, sugar, and lemon juice in a blender until smooth. Strain it twice to remove any seeds or pulp.
To make each mimosa: place strawberry puree in a champagne glass. Add limoncello and stir to combine. Fill the rest of the glass with champagne or sparkling wine. Stir gently if desired. Garnish with a half of a strawberry and/or some lemon rind.