Step 1
Combine warm water and yeast in a small bowl and allow to sit until frothy 10 to 15 minutes. Place mushrooms and tomatoes in a bowl and cover with warm water; let stand for 5 minutes. Drain mushrooms and tomatoes chop coarsely and set aside.
Step 2
Combine flour and cane sugar together in a large bowl. Add yeast mixture and olive oil. Stir well until mixture becomes kneadable; knead until well-blended. Add another 1 or 2 tablespoons of water only if needed to make dough moist enough. Turn dough onto a lightly floured surface and knead well for 5 minutes.
Step 3
Grease a bowl with olive oil. Form dough into a ball and place in the bowl; roll around to coat with oil. Cover the bowl with a damp towel and allow dough to rise in a warm place for 1 hour.
Step 4
While dough rises heat canola oil in a deep saucepan over medium heat. Add garlic and cook until lightly golden 1 to 2 minutes. Add green onions and cook for 1 minute. Add celery and cook for 1 minute. Add drained and chopped mushrooms and tomatoes; cook for 1 minute. Add zucchini and cook for 1 minute. Add bok choy and cook for 1 minute. Add spinach and cover the pan. Cook until wilted 3 to 5 minutes.
Step 5
While vegetables cook combine miso paste tamari and liquid aminos in a bowl. Add mixture to the saucepan with the vegetables and mix well. Remove saucepan from heat and allow dumpling filling to cool until safe to handle 10 to 15 minutes.
Step 6
Punch dough down in the bowl; let rest 15 minutes more. Transfer dough to a floured work surface and roll into a 12-inch log. Cut log into 24 even pieces. Use a rolling pin to roll each piece into a 3-inch circle.
Step 7
Put 1 heaping teaspoon filling in the center of each dough circle. Bring edges up like a pouch twist and press down gently to seal.
Step 8
Place a wet paper towel or a cabbage leaf inside a steamer insert and arrange dumplings on top. Allow dumplings to rise for 15 minutes.
Step 9
Place steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Steam dumplings until they appear shiny 10 to 12 minutes.