In a mixing bowl, combine the vegan yogurt, tahini, lemon juice, minced garlic, and salt. Taste and adjust seasonings if needed. Set aside.
Using a peeler or mandoline slicer, very thinly slice the cucumber into long strips. You want the strips to be very thin. Transfer the sliced cucumber to the mixing bowl and stir to coat with the yogurt dressing. Cover and refrigerate while you prepare the tempeh and omelet.
Heat the oil in a non-stick skillet over medium heat. Once hot, shallow-fry the tempeh until golden brown, flipping it once.
In the meantime, combine the sesame oil, white miso, white vinegar, and maple syrup in a small bowl.
Deglaze the skillet with the miso sauce and stir to make sure the tempeh is coated with the sauce. Remove from heat and set aside.
Add the silken tofu, chickpea flour, nutritional yeast, onion powder, salt, baking powder, and turmeric to a high-speed blender. Blend on high speed until smooth, about 10 seconds.
Heat a non-stick skillet over medium heat. Once hot, add a teaspoon of oil and spread it evenly using a kitchen paper towel.
Pour half of the batter into the skillet and spread it into an 8-inch round using the back of a spoon. Cover with a lid and cook for about 4 minutes, or until the top appears cooked. Carefully and quickly flip the omelet and cook for another 2 minutes on the other side. Transfer to a serving plate and repeat with the rest of the batter.
Top the omelet with about ⅓ cup of cucumber salad, a few slices of miso tempeh and some greens. Garnish with a few mint leaves and serve immediately.