Combine mustard, cream cheese, lemon juice, salt, and black pepper in a bowl. Thoroughly mix until smooth.
Add salmon and stir well. Add tomatoes, cucumber, red onion, and capers and toss lightly to mix.
Season with additional salt and black pepper, if desired. Dig in!
PER SERVING (1 heaping cup): 136 calories, 2g fat, 745mg sodium, 7g carbs, 1g fiber, 3g sugars, 20.5g protein