In a small bowl, mix cumin, paprika, cayenne, 1 teaspoon salt, and 1/2 teaspoon pepper.
Coat chicken in dry rub and set aside.
Meanwhile, prepare salad dressing.
In a medium jar, add egg yolk, mustard, garlic, Worcestershire, lemon juice, olive oil, 1 teaspoon salt, and 1/2 teaspoon pepper.
Shake vigorously; refrigerate until ready to use.
In a medium skillet over medium-high, heat remaining olive oil.
Cook chicken until golden brown, about 4 per side.
Repeat with remaining chicken.
Let rest 5, then slice.
In a large bowl, toss romaine with dressing.
Serve with chicken, Mexican cheese, croutons, and lemon.