Preheat the oven to 400 degrees.
Tear four pieces of aluminum foil into 12-14 inch pieces.
Toss the prepped asparagus with 2 teaspoons of the olive oil and season with salt and pepper to taste.
Divide the spears between the 4 sheets, laying in a single layer in the center of each piece of foil.
Place salmon over the asparagus and spread 3-4 tbsp pesto over the top.
Drizzle 1 tsp. lemon juice over each fillet.
Toss cut tomatoes with the remaining 1 tsp. olive oil and salt to taste.
Spread the tomato halves over each salmon filet.
Wrap the sides of foil in (not too tightly) and roll up the edges to seal into a packet.
Place the packets on a baking sheet and bake in a preheated oven until the salmon has cooked through, about 20 - 25 minutes or until flaky (cooking time will vary depending on the thickness of the salmon).