Place garlic in a food processor; pulse until chopped, about 5 seconds. Add shallot; pulse until chopped, about 5 seconds. Add herbs, lemon (or lime) juice, oil, yogurt, salt, honey and pepper (or crushed red pepper); process until totally combined and smooth, about 1 minute, scraping down sides as needed.
Place tuna in a medium bowl and gently flake with a fork. Pour half of the dressing (about ⅓ cup) over the tuna; stir to combine. (Reserve the remaining dressing for another use.) Garnish with herbs and pepper, if desired.
