From lemon, grate all zest and squeeze 1⁄4 cup juice; set aside.
Heat large covered saucepot salted water to boiling on high. Add green beans; cook 1 minute. Add asparagus; cook 2 to 4 minutes or until vegetables are tender. Drain well.
While water is heating, in 10-inch skillet, cook bacon on medium 8 minutes or until crisp, stirring occasionally. With slotted spoon, transfer bacon to small plate. To rendered fat in skillet, add shallots; cook 3 minutes, stirring. Whisk in reserved lemon juice and 1⁄2 teaspoon each salt and pepper.
In pot used to cook vegetables, toss shallot mixture with vegetables; transfer to serving platter. Top with bacon, pecans and reserved lemon zest.