Bring a large pot of lightly salted water to a boil. Cook angel hair pasta in the boiling water, stirring occasionally, until tender yet firm to the bite, 4 to 5 minutes. Drain, reserving 1 cup pasta water.

Melt 1 tablespoon butter in a large skillet over high heat. Add shrimp; sauté until no longer pink, about 5 minutes. Transfer shrimp to a bowl using a slotted spoon, retaining liquid in the skillet.

Reduce heat to medium-high. Add onion and garlic to the skillet; cook until onion is translucent 5 to 7 minutes. Add tomatoes; cook and stir until tomatoes soften, about 5 minutes.

Add asparagus and pasta water to the skillet; bring to a simmer and cook until asparagus are tender, about 5 minutes. Stir in shrimp and pasta; cook until shrimp are completely opaque in the middle, 2 to 3 minutes. Season with salt, sprinkle with Parmesan cheese, and serve with lemon wedges.