VELVET: cut the chicken into small, ¾ inch pieces. To a bowl, add 1 tablespoon water, baking soda, ½ teaspoon kosher salt, sugar, white pepper, garlic powder, and 2 teaspoons soy sauce. Stir well with a spoon until the baking soda dissolves. Add the chicken, sprinkle with cornstarch, stir, and let sit for 10 minutes.
SAUCE: While the chicken is velveting, in a bowl, add the preserves, rice vinegar, remaining 2 teaspoons soy sauce, red pepper flakes, and 2 tablespoons water in a measuring cup. Whisk to combine.
FRY: Add 2 tablespoons of oil to a deep skillet over medium-high heat. Add ½ of the chicken and cook on one side undisturbed for 2-3 minutes before flipping and cooking the other side for another 2-4 minutes, adding the jalapeño slices during the last 30-45 seconds, in the last batch. When the chicken is golden and cooked, remove to a plate along with the jalapeños. Add more oil as needed, and cook the rest of the chicken.
SAUTE: Drop the skillet temperature down to medium-low. Add the garlic to the remaining oil in the pan and cook for 45 seconds. Pour the sauce into the skillet and let it sizzle and thicken, 45 seconds. When bubbly, add the chicken and jalapeños and toss to combine. Add the diced peaches for the last 30 seconds. Toss one last time, and remove from heat.
SERVE: To serve, scoop jalapeño peach chicken over fluffy rice, sprinkle with sesame seeds if desired, and serve with your favorite steamed veggies on the side.