How to Make It
In a small saucepan, toast the coriander seeds over moderate heat until fragrant, about 2 minutes. Add the vinegar, sugar, orange zest, lavender flowers and 1 tablespoon of kosher salt and bring to a boil, stirring to dissolve the sugar and salt. Add the lime juice, clementine juice and chile. Let the brine cool completely, about 45 minutes.
Strain the brine into a medium bowl. Add the grapes and let pickle at room temperature for 15 minutes. Drain the grapes, return them to the bowl and stir in 1/4 cup of the olive oil. Reserve the brine for another use.
Season the snapper fillets with salt and pepper. In a large nonstick skillet, heat the remaining 1 tablespoon of olive oil until shimmering. Add the fillets skin side down and gently press with a spatula to flatten. Cook over moderately high heat until the skin is crisp, about 3 minutes. Turn the fillets and cook until white throughout, about 2 minutes longer. Transfer to a platter or plates, spoon some of the pickled grapes on top and serve.