Whisk 1 tablespoon oil, 1 tablespoon lemon juice, 1 garlic clove, 1/2 teaspoon lemon peel in glass baking dish. Sprinkle salmon with salt and pepper; add to baking dish and turn to coat. Let salmon marinate at least 15 minutes and up to 30 minutes.
Preheat to 400°F. Brush large rimmed baking sheet with oil. Arrange salmon on oiled sheet. Toss snap peas with remaining marinade in dish. Sprinkle salmon with dill seed and place slices of lemon on top.
Roast salmon until just opaque in center and sugar snap peas until tender, about 8 minutes.
Serve on top of a bed of risotto and sugar snap peas.