Begin by washing and slicing your mixed mushrooms. Make sure to remove any dirt without soaking them in water.
In a large skillet, heat 2 tablespoons of extra-virgin olive oil over medium-high heat.
Add the sliced mushrooms to the skillet in a single layer. Avoid overcrowding the pan.
Sprinkle the heaping teaspoon of sea salt over the mushrooms and cook for about 5-7 minutes, stirring occasionally.
Add the minced garlic to the skillet and sauté for an additional minute. Then, pour in the rice vinegar and tamari.
Remove the skillet from heat and stir in the finely chopped fresh tarragon and freshly ground black pepper.