Toast the pistachios in a small, dry skillet over medium heat for 3–4 minutes until fragrant; transfer to cool.
Pat chicken dry; season all over with 0.6 g of the sea salt and 0.3 g of the white pepper. Prep strawberries and mint.
Glaze: In a blender, combine ¾ cup (≈112 g) strawberries, tomato paste, 0.15 g salt, and 0.05 g pepper; blend until smooth. Pour into a small bowl. Do not rinse the blender.
Vinaigrette: To the same pitcher, add remaining ¾ cup (≈112 g) strawberries, white balsamic vinegar, 0.5 g salt, and 0.35 g pepper; blend until liquefied. With blender on low, slowly drizzle in the olive oil until emulsified.
Heat a large non-stick skillet over medium-high until very hot (≈205°C/400°F). Sear chicken 3–4 minutes per side until golden and cooked through. In the final minute, brush tops with glaze; flip and sear 30 seconds more. Chicken is done at 74°C/165°F.
Rest chicken 5 minutes, then slice. In a large bowl combine spinach, pistachios, cottage cheese, torn mint, and remaining strawberries.
Drizzle about half the vinaigrette over the salad and toss gently. Divide among three plates, top with sliced chicken, and serve with remaining vinaigrette.