Heat oven to 400 degrees F.
Toast almonds on baking sheet for about 5 minutes; remove from oven and cool.
Roughly chop (or process briefly in food processor) the almonds, garlic, chili flakes and lemon zest.
In heavy pan, sauté Brussels sprouts in olive oil over medium heat, stirring occasionally for 8 to 10-minutes until tender. If needed, add 1/8 cup of wine or water and cover for a few minutes to cook thoroughly. Season with salt.
Toss with the pesto and serve.