To a large bowl, add the romaine lettuce, corn, tomatoes, cucumber, optional serrano chile; set aside.
To a medium skillet, add the olive oil, shrimp, evenly sprinkle with Tajin, and cook over medium-high heat for about 2 minutes.
Flip shrimp over, turn the heat to medium-low, add the butter, garlic, evenly season with salt and pepper, and stir in the butter until it melts, about 1 to 2 minutes.
Add the lemon juice, honey, stir to combine, and taste the sauce. If desired, add additional lemon juice, honey, salt, pepper, or Tajin.
Transfer the shrimp and all the sauce to the bowl with the lettuce and vegetables. Stir to combine. Taste and make any other seasoning adjustments if necessary (I sprinkled with 1 more teaspoon Tajin) and serve immediately.