In a large, deep skillet, melt the butter over medium-high heat. Add the shrimp, garlic, 1/2 teaspoon salt and 1/2 teaspoon pepper. Increase the heat to high and cook, stirring often, until the shrimp are just opaque, about 4 minutes. Squeeze the lemon halves over the shrimp.
In a small bowl, mash the chipotles with the adobo sauce. Spread the paste in a thin layer on each tortilla. Cover half of each tortilla with a single layer of shrimp. Sprinkle the cheese over the shrimp; fold the tortillas in half.
Cook one meal now: In a large nonstick skillet, working in 2 batches, cook 2 quesadillas, cheese side down, over medium-high heat until golden, about 2 minutes on each side. Cut into wedges.
Freeze two meals for later: Wrap each quesadilla in foil and stack 4 each into 2 resealable 1-gallon freezer bags; seal, label and freeze. THAW the quesadillas at room temperature for 2 hours. Cook as directed in Step 3.