For cucumbers, slice lengthwise and then into thin diagonal slices. In a bowl combine vinegar, sugar, and salt. Combine until salt and sugar dissolve. Add cucumbers and put them in the fridge to brine.
Pat dry chicken thighs and season with salt all over. Place the chicken skin side down into a dutch oven or large pot on medium heat. Cook undisturbed until golden brown and crisp, about 8-10 min. Then, slide the chicken around for even browning and continue until its a deep brown color, 1-2 min. Transfer chicken to a plate.
Over medium-low heat, add shallots, garlic, ginger, and crushed red pepper to the pot and cook until fragrant, 2 min. Rinse the rice, then add into the pot and stir for 2 min. Stir in soy sauce, a pinch of salt, and coconut water. Add chicken back into the pot skin side up. Increase the heat to medium and bring the liquid to a simmer. Immediately cover pot, reduce the heat to low, and cook 25 min. Remove from heat and let chicken and rice sit 10 minutes.
Assemble the dish, serving the chicken and rice with peanut sauce, cucumbers, and some fresh cilantro.