Cook the potatoes by washing, peeling, and cutting Yukon potatoes into bite-sized chunks. Steam in an Instant Pot with 2 cups of water for 3 minutes or boil for about 5 minutes until fork-tender.

Soak raw cashews in boiling water for at least 30 minutes, then drain and rinse under cold water.

In a blender, combine soaked cashews, filtered water, distilled vinegar, maple syrup, olive oil, garlic, salt, and pepper. Blend until smooth and creamy.

Transfer cooled potatoes to a large bowl. Pour over tzatziki sauce and fold gently. Add chopped green onions and red onion, mixing until well incorporated.

Taste and adjust seasoning. Cover with plastic wrap or transfer to an airtight container. Chill in the refrigerator for at least 1-2 hours before serving.