Day 1: Cut the cabbage into 2-inch squares—separating the layers as much as possible—and toss them into a large glass or ceramic bowl. Add the carrot, daikon and scallions. Dissolve the salt in the water and pour over vegetables. Weight them under a plate and let them sit overnight or for 8–12 hours.
Day 2: Combine the sweet rice flour with water in a small saucepan. Heat the slurry on medium-low—stirring constantly until it thickens, about 5–7 minutes. Remove from the heat and set aside to cool to room temperature. Combine the garlic, ginger and red pepper and grind to a paste using either a food processor or mortar and pestle. Add the spice paste to the rice mixture and combine well. (I recommend wearing kitchen gloves.)
Drain the weighted veggies—reserving 2 cups of soaking brine. Taste for saltiness, and rinse if they’re unpleasantly salty. (They should taste like the ocean.) Mix the spice paste thoroughly into the veggies and don’t worry if it’s quite thick.
Tightly pack the kimchi into a wide-mouth quart jar. When completely packed, press down to force flavor sauce up and over the top of the kimchi. Add some of the reserved brine if necessary to completely cover the veggies. Place a lid over the jar and let the kimchi ferment on the countertop for up to five days—pressing it down so it gets re-covered with sauce, and tasting daily to see how the fermentation is progressing. When soured to personal preference, place the jar in the refrigerator where it will keep for up to three months.