Arrange a rack in center of oven; preheat to 450°. Place a large cast-iron skillet on rack to preheat.
Pat salmon dry; season all over with 1 teaspoon salt and a pinch of pepper. Spread harissa onto salmon flesh. Sprinkle each fillet with everything bagel seasoning.
Carefully remove skillet from oven and drizzle with 2 tablespoons oil. Arrange salmon in skillet skin side down. Bake until flesh becomes opaque and easily flakes with a fork, 10 to 12 minutes.
Meanwhile, in a small bowl, whisk cream cheese, half of shallot, 1 tablespoon dill, 1 tablespoon lemon juice, 2 tablespoons water, and remaining 1 tablespoon oil until smooth; season with a pinch of salt. In another small bowl, soak remaining shallots with remaining 1 tablespoon lemon juice.
In a large bowl, toss arugula, tomato, cucumber, capers, marinated shallots, and remaining 3 tablespoons dill. Add half of dressing, toss to combine, and top with bagel chips.
Divide salmon among plates. Serve with salad and remaining dressing alongside.
Recipe by 5* trending recipes with videos at https://food.theffeed.com/2023/03/14/everything-bagel-crusted-salmon/