Is it possible to extract juice from these vegetables using a blender? How much would it take to produce 100mL of juice?  Baby bok choy:    Napa cabbage:   
The way I do it is put 1-2 tbsp of oil in my pot, add 1/3 cup or so of corn, cover, and heat on medium until it starts popping, then turn down a bit and shake the pot occasionally until it is all popped. So, not oil free, but not a whole lot of oil either. 