Heat water to 122°. While water heats to temperature, season salmon fillets with lemon zest, salt and pepper and place 2 fillets in each bag. Add 2 thyme sprigs per bag and add olive oil. Seal bag.
Once water reaches 122°, set the cooking time to 40 minutes and add salmon.
Heat a nonstick pan over medium-high heat and salmon. Sear on both sides, until golden.
To make the salsa, add watermelon and all remaining ingredients. Toss together to combine. Adjust seasonings and ingredients where necessary.
*you will need 2 ziplock-type bags or 2 small vacuumed sealed bags for the salmon fillets. Place 2 fillets in each bag.
*if you are not using the sous vide method, pat salmon dry and season with kosher salt and pepper. Heat a 10-12” nonstick pan over medium-high heat. Add 2 tablespoons of oil and sauté on both sides for 4-5 minutes each side. Add 1 teaspoon of butter, thyme sprigs and lemon zest. As butter begins to melt, spoon the mixture over the salmon. Serve with watermelon salsa.