In a medium saucepan, bring 1 ½ cups coconut milk to a boil. Stir in the rice and 1 tablespoon olive oil. Cover, and cook for 20 minutes. Remove from the heat and rest 10 minutes. Fluff with a fork and set aside.
In a large cast iron or non-stick skillet, heat 1 tablespoon of olive oil over medium-high heat. Saute the shallot until soft, about 3 minutes. Add the garlic and cook another minute until fragrant. Stir in the bok choy, chard, and tatsoi. Sauté until beginning to wilt, about 2 minutes. Add the lemon juice, coconut milk, and soy sauce. Simmer until the chard stems are tender and the liquid is reduced by half, about 4 minutes more. Taste for seasoning and add more salt as necessary. Transfer to a bowl.
Rinse out the skillet and wipe clean. Coat the pan with a thin layer of olive oil and set it over a high flame.
Add the millet flour to a large plate. Dredge the fish fillets with the flour until well-coated, shaking off any excess. Fry the fish in batches until golden brown and crispy, about 2 minutes per side. Remove to a plate lined with paper towels and repeat with the remaining fish. Season with salt and pepper.
To make the tartar sauce:
In a small bowl, stir together all the ingredients (mayonnaise, whole grain mustard, capers, dill, 2 teaspoons shallots, 2 teaspoons lemon juice)
Taste for seasoning. Tartar sauce can keep for up to a week in the fridge