1. Rinse salmon and cut across fillet into 1/2-inch-thick slices. Rub with olive oil. Lay pieces slightly apart in a lightly oiled 10- by 15-inch baking pan and sprinkle with salt and pepper.
2. Cut zucchini into sticks 1/2 inch thick and 3 inches long. In a 10- to 12-inch frying pan over high heat, bring broth to a boil. Add zucchini and beans; stir occasionally until barely tender when pierced, 1 to 2 minutes. With a slotted spoon, transfer vegetables to a plate. Add wine to broth and boil over high heat until sauce is reduced to 1/2 cup, 8 to 10 minutes. Add butter, cooked vegetables, and tomato and stir gently until hot, about 1 minute; keep warm.
3. Meanwhile, broil salmon about 3 inches from heat until opaque but still moist-looking in center of thickest part (cut to test), about 4 minutes.
4. Working quickly, lay a hot galette piece on each of four warmed dinner plates. Arrange half the salmon equally on galettes; lay another galette piece on each. Top each equally with remaining salmon, then remaining galette piece and any fragments. Spoon vegetables and sauce around napoleons. Top each with a dollop of sour cream and sprinkle with chives.