Preheat the oven to 450°F then line a baking sheet with parchment paper or a silpat. Arrange fingerling potatoes on top, drizzle with 1 tablespoon high heat oil and sprinkle with salt & pepper. Roast in the preheated oven for 30-45 minutes.Meanwhile, combine 1 tablespoon high heat oil with balsamic vinegar and tamari in a large bowl. Add 1 tablespoon chopped rosemary then whisk to combine. Add the diced mushrooms to the bowl and stir until evenly coated. Allow to marinate while the potatoes cook.Once potatoes are done, remove them from the oven and set aside. Scoop the mushrooms out of the bowl (while reserving the liquid) and add them with the beans to the pan with the potatoes. Place back in the oven for about 5-7 minutes, until everything is heated through.Add the chopped greens to a bowl, drizzle with olive oil and sprinkle with salt. Gently massage for about 10 seconds then divide between 4 bowls for serving.In the bowl with the reserved liquid, add the tahini with a few tablespoons of water and whisk until smooth. Add more water as needed, or another tablespoon of balsamic, if desired. Add salt to taste.Arrange cooked potatoes, mushrooms and beans in the bowls with the greens then serve warm with tahini sauce and enjoy!