Heat the oven to 425F with the rack in the upper third.
Toss the green beans with half the oil, the garlic and half the salt on a sheet pan. Roast them alone for 10 minutes; the stagger is the recipe.
Pat the fillets dry, rub with the remaining oil and salt, and nestle them skin side down among the beans.
Bake 10 to 12 minutes more, until the salmon flakes at the thickest point under gentle pressure but still looks translucent at its very center, about 125F for medium.
Meanwhile, toast the sliced almonds in a dry skillet over medium heat, 3 to 4 minutes, tossing often; they go from golden to burnt in under a minute.
Squeeze the lemon half over the finished pan, scatter the almonds across the beans, and serve with the wedges.