Heat olive oil in a large skillet over medium heat and cook garlic until fragrant, about 30 seconds. Add asparagus and stir-fry until tender but still firm to the bite, 5 to 7 minutes. Season with salt and drizzle with lemon juice. Place in a bowl and add cherry tomatoes.
Stir vinegar, mustard, sugar, and salt together in a small bowl. Pour in olive oil and mix well. Drizzle dressing over asparagus and tomatoes and mix well. Serve warm.