In a large bowl, combine flour, baking powder, and 2 tablespoons sesame oil, and whisk to combine. Gradually whisk in water, mixing just until moistened and lumps are gone. Do not overmix. Heat 4 inches canola oil in a large pot to 325°F. Line 2 sheet pans with two layers of paper towels.  Working in batches, using tongs, dip vegetables into batter and fry just until crispy , about 1 to 2 minutes. Transfer with a slotted spoon to the prepared pans, and sprinkle with salt. In a small bowl, combine soy sauce, lime juice, and remaining 1 tablespoon sesame oil; whisk to combine. Serve fried vegetables immediately with the dipping sauce.