Pre-heat the oven to 350.
Heat the olive oil in an oven-safe skillet over medium heat.
Sprinkle the chicken thighs with salt and pepper, then dredge both sides in flour. Add them, skin side down, to the pan and cook them, until the skin is golden- about 3 to 4 minutes. Turn them to the other side and cook for another couple of minutes, then remove them to a plate. If there is excess grease, pour off.
Add the onions, ginger and garlic to the pan and stir to cook- about 3 minutes. Pour in a 1/2 of the broth, then stir and let it reduce for 1 to 2 minutes- scraping the bits of the bottom of pan. Add in the other 1/2 broth vinegar, brown sugar, red pepper flakes, and soy sauce. Sprinkle in a little salt and pepper, and let it cook for 1 to 2 minutes, stirring continually.
Nestle the chicken thighs back into the pan, skin side up. (They should not be submerged; the liquid should come up about halfway up the sides of the chicken.) Add the pineapple. Place the lid on the skillet and place it in the oven. Let it cook in the oven for 15 minutes. Remove the lid, then spoon the sauce onto each chicken thigh. Continue cooking in the oven with the lid off for 15 minutes, making sure it doesn't get too brown.
Serve the chicken with the rice, spooning sauce over the top.