Slice calamari tubes into thin rings. If any tentacles are too thick, slice in half.

Add calamari to a large bowl with avocado oil, salt, lemon slices, half the lemon juice and half the garlic. Toss to combine. Place in the refrigerator for 20 minutes, or up to 1 hour.

While the calamari is marinating, prepare the lemon-butter sauce. In a small sauce pan on medium, add butter, wine, remaining garlic and lemon juice and whisk for 1 minute. Cover, turn off heat and set aside.

Preheat your grill or grill pan to medium high heat.  If using a grill, place calamari and citrus slices on a grill rack and place on the grill. If using a grill pan, place directly on the pan.

Grill calamari until opaque, about 3 minutes. Remove from heat.

Toss the arugula, red onions, and tomatoes. Top with grilled calamari and serve with lemon-butter sauce.