Grill salmon, covered with grill lid, over medium-high heat (350° to 400°) 5 minutes on each side, until fish flakes with fork. Cool; and flake.
Spoon salmon evenly over 4 tortillas; top evenly with cheeses and pepper slices, cover with remaining tortillas.
Cook tortillas in a large nonstick skillet over high heat 1 minute on each side or until tortillas are lightly browned and cheese melts. Cut each into 4 triangles, and top with Cucumber Salsa and fresh cilantro sprigs, if desired.