Mix the avocado oil, dijon mustard, and lemon juice together. Brush this mixture all over the chicken thighs.
In a small mixing bowl, combine the kosher salt, granulated onion and garlic, smoked paprika, and fresh ground pepper together. Sprinkle this spice blend all over the chicken thighs.
Grab a sheet pan. Line said sheet pan with parchment paper or foil to make clean up easy. Place an oven-safe rack in the sheet pan and spray or wipe with just a little avocado oil.
Place the seasoned chicken thighs, skin-side up onto the rack. Roasted in a preheated 425° oven for about 35-40 minutes or until they reach an internal temperature of 165°.
If you would like the skins to be more crisp at this point, simply crank up the broiler and give them a couple of minutes under the high heat.
Remove the Roasted Chicken Thighs from the oven and let them rest 10-15 minutes.