I would remove the worst leaves, but not all at once to avoid further stress to the plants.They will most likely dry up if they're chewed really bad and then you can remove them. I'm thinking netting might work, if it's fine enough so the grasshoppers can't get through. The tomato plant has leaf miners, that's whats causing those little white tunnel looking things on the leaves. They are usually harmless to the plant, it's just cosmetic damage. This is the first time I've seen leaf miners on a tomato, I've previously only seen them on columbines.