The spicy-sweet sauce is terrific with rich, meaty salmon. Other oily fish, such as ocean trout or mackerel, would work well, too.
Preheat broiler with rack 4 inches from heating element. Lightly brush salmon with oil; season both sides with salt and pepper. Place, skin-side up, on a lightly oiled broiler pan or a rimmed baking sheet lined with an oiled wire rack. Broil until skin is crisp, about 3 minutes. Flip; broil 1 minute. Generously brush with some of sauce and continue to broil until fish is just cooked through and browned in spots, 2 to 3 minutes more.
Meanwhile, toss fennel, radishes, and cilantro with oil and lemon juice; season with salt and pepper. Serve salmon with salad, lemon wedges, more cilantro, and remaining sauce.