In a large nonstick skillet, cook sausage over medium heat until no longer pink, breaking into smaller pieces, 4-6 minutes. Remove from pan.
In a small bowl, whisk eggs and egg whites until blended. In same pan, add eggs; cook and stir over medium heat until eggs are thickened and no liquid egg remains. Remove from pan; wipe skillet clean if necessary.
In skillet, heat oil over medium-high heat. Add spinach, tomatoes and garlic; cook and stir until spinach is wilted, 2-3 minutes. Stir in sausage and eggs; heat through. Season with salt and pepper.
To serve, spoon 2/3 cup filling across center each tortilla. Fold bottom and sides of tortilla over filling and roll up. If desired, top with salsa.