Peel and finely chop onion. Peel and thinly slice garlic cloves. Rinse ⅔ cup white rice in a fine-mesh sieve until water runs clear.
Add the onion to a good lug of olive oil and cook over medium heat, stirring occasionally, until onion is translucent and beginning to take on some colour.
Pour in 8 cups water and stir to combine. Stir in rice, chicken thighs, and a healthy pinch of salt. Bring to a boil, then reduce heat to low and bring to a gentle simmer. Simmer, uncovered, until chicken is cooked through, about 20 minutes.
Using tongs, transfer chicken to a plate and let sit until cool enough to handle. Shred meat with two forks. Continue to simmer soup while you’re prepping the rest of your ingredients.
Strip kale leaves off of thick center ribs from 1 bunch Tuscan kale, discarding ribs. Rinse kale thoroughly in cold water, shake off excess water, then thinly slice leaves crosswise.
Add kale and shredded chicken to pot. Continue to simmer, stirring occasionally, until kale is bright green and chicken is warmed through, about 4 minutes.
Remove pot from heat. Squeeze in lemon juice, season with salt, and stir to combine.
Divide soup among bowls. Drizzle with Lao Gan Ma. Tear some sprigs of dill over, then top with black pepper.