Combine mayonnaise, lemon juice, minced garlic, and black pepper in a small bowl; set aside.

Preheat grill or grill pan over medium-high heat.

Brush both sides of zucchini slices with olive oil.

Grill zucchini for 2 minutes per side or until lightly browned. Remove from grill.

Repeat grilling procedure with remaining zucchini slices.

Layer the bottom half of the focaccia with provolone cheese.

Add the grilled zucchini over the cheese.

Spread the mayonnaise mixture over the zucchini.

Add Grilled Lemon-Herb Chicken (assumed ingredient, not in original list. Assuming chicken needs to be cooked separately beforehand)

Add sliced roasted red bell peppers.

Cover with the top half of the focaccia.

Cut the sandwich into four wedges.

Wrap each wedge in foil or parchment paper; chill before serving.