Start by using a pair of kitchen shears to cut open the belly of each smelt. You’ll see some black stuff inside the smelt. Use a thin stream of cold running water to rinse it out. Pat the smelts dry with a paper towel or let them air dry in a colander. Then toss the smelts with the clear rice wine and salt, and set aside.
In a large bowl, make the batter coating. Add the cornstarch, flour, water, vegetable oil, baking soda, and sesame oil. Whisk thoroughly. Toss the smelts in the coating.
In a small bowl, make the seasoned salt mixture by combining the salt, white pepper, sugar, and five spice powder (if using). Set aside.
Heat the peanut or canola oil in a small pot to between 250-275°F (120-135°C). (If you like, you can use a larger pot to fry larger batches, but you’ll use up more oil that will end up tasting vaguely fishy even if you do decide to use it in other dishes.)
Add the garlic to the oil, and cook until it just starts to turn color (30 seconds). Be careful not to brown the garlic, or it will be bitter. With a fine-meshed strainer or large spoon, scoop it out onto a plate lined with paper towels to drain (it should be slightly crispy).
Turn up the heat, bringing the oil up to 350°F/175°C. Quickly but carefully lower the smelts into the hot oil one at a time. Be sure to place the fish away from the others as you fry so they don’t stick together. The oil temperature will come down each time you add new pieces, so adjust the heat to maintain the temperature.
Fry until light golden—about 1½ to 2 minutes is enough to cook the fish, depending on the size of the smelt.
Place on a rack to drain and continue frying in about 5 total batches. As the smelts come out of the oil, sprinkle a pinch of the seasoning salt over each batch. Be sure to reserve some of your seasoning salt to finish the dish later.
This next step is optional. If the smelts are particularly fresh, or you don’t mind them being only slightly crispy, a second fry is not needed. The fish will be more tender with a single fry. That said, if you like a crispier smelt or if you fried the smelt in advance, then you can go for a very short second fry. To do that, let the oil temperature come back up to 350°F/175°C, and add the smelts back to the oil in batches for 15-30 seconds, or until crispy. You can likely do this in just 3 batches, as there’s no longer a risk of the smelts sticking together.
Transfer the crispy fried smelts to a serving platter. Heat a dry wok over high heat until just smoking. Reduce the wok to medium-low. Add the green peppers and toss for about 20 seconds—just until they turn fragrant.
Turn off the heat and add the fried garlic, sliced shallots, and the remaining seasoning salt. Mix. Add the smelts, and gently toss everything together. Serve immediately.