Combine lemon juice, Dijon, and garlic in a small bowl. Add olive oil, and whisk until thoroughly combined. Season to taste with salt and freshly ground black pepper.
Bring a large pot of water to a boil. Add asparagus, and cook for 1 minute. If your spears are thick, you can leave them in a little longer, just be sure to not overcook. They should be crisp to the bite.
Drop asparagus into a bowl of ice water. Once completely cold, drain asparagus and diagonally slice the spears into 1-1/2 to 2 inch pieces. Place on a paper towel to dry.
Combine asparagus, tomatoes, red onion, and feta in a large bowl. Drizzle the dressing over the salad, and gently toss until well coated. Serve with hard boiled egg wedges, if desired.
