First, prepare your chive flowers. These are Chinese chive flowers, which are white, rather than purple. But you can sub in regular Chive flowers. But if you have a chance, grow Chinese chives in your back yard. They grow like weeds! Heat your oil in a small, relatively deep pot to 375 degrees. (Another way to test oil temperature is to stick a bamboo chopstick into the oil. If bubbles start sizzling around the chopstick, the oil is ready).
While you're waiting for that, whisk together the flour, cornstarch, and seltzer water in a medium bowl. Prep the dipping sauce by combining the soy sauce, water, sugar, and rice wine.
Using a fork, coat the flowers in the batter. Gently tap the fork on the side of the bowl to get rid of the excess batter. Fry up to 5 flowers at a time. When they get just golden, transfer to a plate lined with a paper towel.
Sprinkle the hot tempura with a bit of sea salt as you fry, and serve immediately!