In a high-speed blender, combine strawberries, raspberries, lemon juice, honey, water, vanilla extract, and sea salt. Blend on high speed for 60-90 seconds until completely smooth and no chunks remain.

Add the citric acid powder to the blended mixture and pulse for 10-15 seconds to incorporate evenly. Taste and adjust sourness level by adding more citric acid if desired.

Pour the blended mixture through a fine-mesh strainer into a bowl to remove any seeds or pulp, pressing with a spatula to extract all liquid. This creates a smoother texture for the strips.

Line a large baking sheet with parchment paper or a silicone baking mat. Make sure the surface is completely flat and level for even freezing.

Pour the strained fruit mixture onto the prepared baking sheet and use an offset spatula to spread it into a thin, even layer about 1/8 inch thick. The thinner the layer, the easier it will be to create strips.

Place the baking sheet in the freezer on a flat surface and freeze for 4 hours or until completely solid throughout. Do not disturb during freezing.

Remove from freezer and immediately cut the frozen sheet into strips about 1 inch wide and 4-5 inches long using a sharp knife or pizza cutter. Serve immediately or store in an airtight container in the freezer for up to 2 weeks.