Add the pineapple, kiwi, lime juice and water to a high speed blender and blend on high until it is pureed. Avoid filling your blender more than two-thirds of the way full. Work in batches if needed.
Strain the pulp using a medium sieve. (Optional but recommended)
Pour the fresca into a large pitcher or jar and taste for sweetness and acidity. Add your sweetener of choice and more lime juice according to taste. Finally stir in chia seeds. Mix well to avoid clumps, and refrigerate for 10-15 minutes or until ready to serve.
You will have to stir again as the chia seeds will settle with time - this is totally normal.
Store leftovers in an airtight container for up to one day.
Filtering your drink is totally optional, If you want extra fibre in your diet and don’t mind the gritty texture you can keep it. Otherwise you can freeze the pulp for later to use in smoothies.