Whisk together tahini, lemon juice, garlic and water. Add salt to taste (about 1 tsp kosher salt).
In a deep saucepan, heat 1-2 inches of canola oil until shimmering hot, or 350ºF. Add shallots and cook until golden brown, stirring frequently. Transfer to paper towels to drain and toss immediately with a good pinch of salt. Try not to eat them all immediately.
Heat 2 tbsp oil in a large skillet over high heat until shimmering. Working in batches if needed to avoid overcrowding the pan, brown fish on one side until it releases easily with a spatula (if it is sticking, it isn't done browning) then transfer to a plate (it'll finish cooking in the sauce). Add another tablespoon of olive oil to the pan and add kale, stirring to just wilt it. Stir in sauce then return fish to the pan and nestle it in, spooning some sauce overtop. Cook a minute or two, until fish is opaque and flakes easily. Top with fried shallots and pine nuts, if desired.