In a large bowl, stir together tuna, egg, cilantro, breadcrumbs, mayonnaise, lemon juice, and jalapeno. Mix gently until ingredients just hold together.
Using a packed 1/3-cup measure of tuna mixture per patty, shape into 8 cakes.
In a large nonstick skillet, heat oil over medium. Working in batches if necessary, cook cakes until golden brown and crisp on the outside, about 2 minutes per side. Serve hot, accompanied by salsa, and garnish with cilantro sprigs.