Coat the top of the fish liberally with the chia mixture, pressing it down well with your fingers, all the way to the edges.
Heat olive oil in a pan over medium heat. Let the pan get hot.
Add the fish, chia seed side down and pan sear 3-4 minutes until golden and crispy . Using a metal spatula, carefully turn over, to keep crust in tact and continue cooking until fish is cooked to desired doneness, 3-4 more minutes, or more depending on thickness.
Divide the fennel slaw between two plates and place fish on top. Squeeze with lemon and top with pickled red onions and fresh dill.
If using salmon with skin, feel free to salt and crisp the skin side too, placing chia mix on the fleshy side.
I find that using a thin metal spatula ( especially in a cast iron skillet) helps to keep the crust ( in this case, chia crust) more intact. Just a personal preference.