2 large red bell peppers – seeded, cored, and chopped
2 bulbs fennel, trimmed and chopped
2 bunches kale, leaves stripped from stems and torn into pieces
1/4 lemon, juiced, or to taste
Whisk 1/2 cup lemon juice, olive oil, Dijon mustard, salt, and pepper together in a large bowl until dressing is smooth.
Bring water, wild rice, and butter to a boil in a saucepan. Reduce heat to medium-low, cover, and simmer until rice is tender, 30 to 45 minutes. Drain excess liquid and cook uncovered until water is completely evaporated, about 5 minutes more. Stir rice and let cool slightly.
Combine cabbage, red bell peppers, and fennel in the bowl with dressing; toss to evenly coat. Place kale on top of the cabbage mixture and spoon warm wild rice over kale; let sit until kale is slightly wilted, 5 to 10 minutes. Toss until salad is evenly mixed, adding more lemon juice to taste.