Prepare pasta according to package instructions until al dente. After draining, toss in a little olive oil to keep it from sticking.
Into a cold sauté pan, add olive oil, garlic, red pepper flakes. Turn heat to medium, allow to slowly warm up. Stir until occasionally until garlic becomes fragrant and starts to sizzle.
Add capers, lemon zest and juice, salt and parsley, cook for about 2 minutes.
Remove pan from heat, add tuna. Stir until tuna is coated with the sauce.
Add the cooked pasta and toss until everything is combined and coated with sauce. Taste and add more salt if needed.