Preheat oven to 400 F and line baking sheet with parchment paper.

In large bowl, whisk together whole grain flour, almond flour, and salt. With pastry cutter, cut in cold butter until it forms pea-sized crumbs. Add cold water, 1 Tbsp at a time, mixing until dough comes together. Shape into disk; place in glass bowl, cover, and refrigerate for 30 minutes.

In skillet, heat 1 Tbsp olive oil over medium heat. Sauté onions until soft, about 5 minutes. Add garlic, paprika, thyme, salt, and pepper, and cook for 1 more minute. Stir in lentils and cook until warmed through, then remove from heat.

Remove dough from fridge, roll out on floured surface into rough 12 inch circle. Transfer to parchment-lined baking sheet. Spread lentil mixture in center, leaving a 2 inch border. Fold edges over filling. Top with crumbled goat cheese and drizzle with honey. Bake in preheated oven for 25 to 30 minutes, until crust is golden and filling is warm. Allow to cool, then slice.

In bowl, toss mixed greens with cucumber, lemon juice, olive oil, sumac, salt, and pepper. Serve alongside galette, once cooled and sliced.