Pounded Beef Tenderloin with Hearts of Palm Salad

Name: Pounded Beef Tenderloin with Hearts of Palm Salad
Ingredients: 1 pound center-cut beef tenderloin, cut crosswise into 4 slices and lightly pounded 1/8 inch thick; 2 tablespoons extra-virgin olive oil, plus more for brushing; Kosher salt; Pepper; 1 1/2 tablespoons fresh lemon juice, plus lemon wedges for serving; 2 tablespoons minced shallot; 1 1/2 teaspoons Dijon mustard; 4 ounces watercress, thick stems discarded (6 cups); One 15-ounce can hearts of palm, drained and sliced 1/4 inch thick on the bias; 1 Hass avocado, peeled and cut into 1-inch pieces; 1/3 cup snipped chives