Combine crabmeat, egg, scallions (if using), mayonnaise, Dijon mustard, salt, and pepper in a large bowl. Add enough breadcrumbs to bind mixture enough to form into cakes. Refrigerate the mixture until you're ready to cook.
Heat a large nonstick skillet over medium-high heat for 2-3 minutes; add oil, and heat until it shimmers. Shape crab mixture into 8 (1-inch-thick) cakes, using 1/3 cup mixture for each; cook, adjusting heat as necessary and gently turning once, until golden brown on both sides (about 5 minutes per side). Serve 2 crab cakes per plate with lemon wedges and Cherry Tomato and Corn Salad.
Note: Most of the sodium in this meal is from naturally occurring sodium in the crab.
