Make the salsa first; combine all ingredients, including grapefruit juice.
Let sit for at least 20 minutes, then taste and adjust the seasoning if necessary.
To prepare the quesadillas, spread one tortilla with cream cheese; sprinkle with chives and add a layer of smoked salmon.
Add shredded Monterey Jack and season with some cracked pepper. Top off with second tortilla round.
Repeat three more times to create four quesadillas.
Heat a nonstick skillet, large enough to fit a quesadilla, and lightly grease with some olive oil.
Place tortilla in pan, and fry slowly until cheese is melted and tortilla is crisp and lightly golden.
Repeat for remaining quesadillas.
Serve quesadillas with salsa and guacamole on the side.