Heat 1 tbsp oil in a 12-inch heavy skillet over medium heat until it shimmers. Add the bread crumbs until crisp and golden brown, about 4 minutes. Transfer to a bowl and stir in the lemon zest and a pinch of salt.
Wipe out the skillet, then add anchovy paste and remaining 2 Tbsp oil and cook 15 seconds. Increase the heat to medium-high and add half the lettuce until slightly wilted, about 1 minute. Add remaining lettuce until wilted, about 2 more minutes. Remove from the heat and stir in the lemon juice, maple flakes, 1/8 tsp salt, and ¼ tsp pepper.